No signal connected

[penny]

My Mums pc has suddenly stopped working. When PC is switched on there is a blank screen with just a little square showing that says "No signal connected". Also, the keyboard Num lock, Caps lock and Scroll lock lights are on all the time. When I press the reset button to turn PC off it doesn't work. So I have to unplug it. Help would be most appreciated.

[ski]

Make sure the video card is fully seated, and its cable is securely connected.
If those are ok, then either the card or its cable may be bad. Try a different card and cable.
If the video adapter is built into the MB, then install a video card and connect a different cable.

Also, you may be able to turn off the system by pressing and holding the power-on button for 4 seconds or longer, instead of disconnecting the power cord.

[penny]

Do I have to go inside PC to check video card? I wouldn't know how to. I have checked the monitor to pc cable and the pins in connections and they are okay.

[ski]

Suggest that someone who has experience with the insides of a PC help you.
If you do not have a friend who qualifies, then another option is to have a repair shop take a look at it.

[Ravenwood]

A couple of other things...

1) Try disconnecting the power compeltely from the machine for at least one minute and letting all the capacitors in the machine completely drain. Then plug it back in and then try powering it back on.

2) If the Num/Scroll/Caps lock lights all come on as soon as you power up the PC and never turn off, then there's most likely something hardware that's wrong with it. These lights turn on and then off (with the exception of wireless keyboard) again when a machine is first powered up. This is part of what is called the POST (short for Power On Self Test).

3) If you have one, try swapping the monitor that your using with a different one. That will eliminate the monitor as the problem

4) When you turn the machine on, can you hear the hard drive working away? And/or is the little flashing light for the drive blinking away? If it's on constant or never turns on, then the system is not booting at all.

If none of these help at all, then Ski is absolutly right, there's most likely some hardware problem that someone with more experience will need to look at.

[penny]

When switched on I can hear PC and fan, but the red light is on all the time. thats why I think it is a fault with PC and not monitor.
I have unplugged for 5 mins and tryed again but still the same. Do you think that one of those bootable discs on Ebay would work?

[Ravenwood]

I don't think that a bootable disk at this point is going to help you since it sounds like the system isn't even completing it's POST (Power On Self Test). Without completing the POST, a boot disk is meaningless...

If it's under warrantee, call the manufacturer or find someone local who can take a look at it (if I remember correctly you were uncomfortable with opening and playing with the insides of the machine).

It could be a bad power supply, failed hard drive or CDROM drive (hence the drive light (red) is on all the time), bad memory or any one of a number of other things...

[ski]

"No Signal Connected" normally indicates a problem either with the video card(or the video adapter built into the MB), the video card's slot, the video cable, the monitor, or the monitor's connector port.

[Sylvander]

Sylvander’s Diagnostic Flowcharts
Download a copy of my diagnostic flowcharts from here
www.erniek.eclipse.co.uk/downloads/sylvanderdiags.zip
and print them to leaf through.
Begin on the STARTUP chart.
Shortly after you switch on the PC do you hear any beep[s], or a total absence of any beep[s].
When the PC worked normally did it emit a single short beep?
-----------------------------------------------------------------------------------
FAILURE TO COMPLETE POST, NO BEEP, NO OUTPUT SIGNAL FROM VIDEO CARD.
www.pcguide.com/vb/showthread.php?t=39685
-----------------------------------------------------------------------------------

[penny]

I have printed the zipped file you posted Sylvander. Will try. And many thanks to Ski and Ravenwood. Please all keep intouch, I do appreciate your advice. .......Woudn't mind but my Mum is 83 of age and just uses her PC for games that I d/load for her. (nothing of interest to be lost by deleting files) lol. I can alwats put them back.

[Ravenwood]

"No Signal Connected" normally indicates a problem either with the video card(or the video adapter built into the MB), the video card's slot, the video cable, the monitor, or the monitor's connector port.

Yes, this is correct, the "No signal detected" is defenetly caused by a signal not getting from the PC to the monitor, but there are many different circumstances that can cause this. If the machine cannot start properly (due to some other hardware failure, CPU, RAM, BIOS, Video, etc...) then a signal will never be generated to tell the monitor to actually turn on, hence the no signal message.

If the hard drive light is staying on constantly (i.e. previously stated that the "red" light comes on that stays on constantly, and the CAPS, NUM, and SCROLL lock lights are staying lit (no blinking on then off), then the machine is not completing it's Power On Self Test (POST). Usually if just the video has failed on a machine, you will get a serries of "beep codes" indicating this. You may also get "beep codes" if there is bad, in-compatible, or mis-configured RAM installed in a machine.

I wasn't dissagreeing that part of the problem could be the video sub-system, I was meerly stating that there may be more wrong with the machine than just the video adapter and someone should hands on look at it (i.e. open it up, reseat the cards, etc).

[ski]

Yes, this is correct, the "No signal detected" is defenetly caused by a signal not getting from the PC to the monitor, but there are many different circumstances that can cause this. If the machine cannot start properly (due to some other hardware failure, CPU, RAM, BIOS, Video, etc...) then a signal will never be generated to tell the monitor to actually turn on, hence the no signal message.

If the hard drive light is staying on constantly (i.e. previously stated that the "red" light comes on that stays on constantly, and the CAPS, NUM, and SCROLL lock lights are staying lit (no blinking on then off), then the machine is not completing it's Power On Self Test (POST). Usually if just the video has failed on a machine, you will get a serries of "beep codes" indicating this. You may also get "beep codes" if there is bad, in-compatible, or mis-configured RAM installed in a machine.

I wasn't dissagreeing that part of the problem could be the video sub-system, I was meerly stating that there may be more wrong with the machine than just the video adapter and someone should hands on look at it (i.e. open it up, reseat the cards, etc).
The only reason why I stated in my previous post that a "No Signal" message "normally" indicates a video problem is simply because I wanted penny to focus on that part of the system before checking other components.
But I do agree with you that the HD and KB lights will stay lit if the system fails to get thru POST. However, I've also seen systems with a bad video card/slot that did not emit any beeps during POST(I've also seen the same thing happen with bad RAM/slot).

[penny]

Turned PC on again today and it did its beeps same as it did when it was working okay. Then some writing came on screen but went off before i could read it all. I noticed something like Start Windows Normally, but it didn't give me a chance what to do. To my amazement it went into Windows and showed the Desktop. Then I got something like, error click for details. Then it said, send error report to microsoft. I couldn't because her PC is not on internet. So I switched PC off again by pressing the start button for 4 seconds. Waited one minute and switched back on again hoping to read the screen again but it didn't beep and no writing on screen. This is really weird!

[mjc]

At this point, since it seems to want to work after sitting idle for a period of time, I would start by replacing the CMOS battery...a coin sized battery located on the motherboard.

[penny]

I think you might be right MJC. I downloaded the Ultimate Boot Disc, burned it onto a CD then put it in my Mums PC. Windows started and showed desktop just for a while and then went off again. I managed to see the clock in bottom right of screen and the time was wrong. Are all PC batteries the same?

[Whyzman]

How old is this PC?

[Whyzman]

You can take the existing battery out and check, but almost all batteries for PCs are identical CR2032.

[penny]

It was a CR2032, so I bought a wrist strap and battery and fitted. Put the boot disc in, and on the screen it says, Press F2 to run setup or press F1 to load default values and continue. Have tried them both but nothing happens.
More help on this please as I am a female 61 year old, lol.

[Sylvander]

"on the screen it says, Press F2 to run setup or press F1 to load default values and continue. Have tried them both but nothing happens."
Is Startup freezing at this screen?

The latest state of play might be...
The BIOS's configuration settings have been reset to the defaults...
But those default settings don't match or work well with the hardware that is connected.
In particular, most likely the video card type doesn't match the type specified to be used by the settings.
e.g your card might be AGP, but the default specifies a PCI video card.
OR...
The default specifies onboard video, but a PCI video card is connected.

Ideally you'd know what the defaults are, and connect the hardware to suit.
Or else you guess what the defaults might be and experiment to try to match them.

EXAMPLE
Yesterday, ErnieK [who had a PCIe video card connected] changed his BIOS setting to PCI and "Save and exit Setup".
The PC managed to boot into Windows, but the BIOS wouldn't let him gain access to the BIOS Setup.
So he connected a PCI video card and the BIOS let him into Setup.
He changed the setting back to PCIe and remove the PCI card and all was well once more.

[penny]

Yes it's freezing at this screen.

[penny]

I downloaded the Bios drivers from Asrock on internet and burned to a cd.
I think it needs a floppy to copy the drivers to, but I don't have a floppy drive on my PC. My mum has one on her pc (the pc that won't boot up).

[Sylvander]

Such drivers [I assume these are mobo chipset drivers] are only used once Windows has loaded into memory [after step 15 below]; your PC isn't getting anywhere near that stage; it's freezing during the BIOS's POST [on step 5], and failing to complete the POST.
Do you know anything about the video [card?] setup, and the normal BIOS configuration settings for video, versus the default video settings?

A typical and successful startup sequence
1. Start of Boot Troubleshooting Walkthrough
http://www.pcguide.com/ts/x/boot/walk/index.htm
2. Yes: The system power supply is functioning
http://www.pcguide.com/ts/x/boot/walk/power1.htm
------------------------------------------------------
You should hear a single short beep at about this point indicating the successful running/completion of the POST.
Some PC’s beep much later, possibly as late as just before step 12.
------------------------------------------------------
3. Yes: Something is being written to the screen during boot up [This may be only a flashing cursor]
http://www.pcguide.com/ts/x/boot/walk/video1.htm
4. The video BIOS message is displayed on the screen for a few seconds and then clears from the screen, or more messages display under it
http://www.pcguide.com/ts/x/boot/walk/vbios1.htm
5. Yes: The system BIOS startup screen is appearing
http://www.pcguide.com/ts/x/boot/walk/bios1.htm
6. The memory test completes successfully
http://www.pcguide.com/ts/x/boot/walk/ram1.htm
7. The BIOS accesses the floppy drives and the boot continues
http://www.pcguide.com/ts/x/boot/walk/seek1.htm
8. The system is able to autodetect IDE devices successfully
http://www.pcguide.com/ts/x/boot/walk/auto1.htm
9. The system is not Plug and Play compatible, has no Plug and Play devices, or has PnP devices but identifies them properly
http://www.pcguide.com/ts/x/boot/walk/pnp1.htm
10. Boot sequence is A: before C: (floppy disk first)
http://www.pcguide.com/ts/x/boot/walk/seqAC.htm
11. The floppy disk makes a noise and the light comes on
http://www.pcguide.com/ts/x/boot/walk/fd1.htm
12. The floppy disk light goes off and the hard disk light comes on as it starts booting
http://www.pcguide.com/ts/x/boot/walk/fd1hdd.htm
13. The hard disk boot process will continue here, if you want to follow it.
http://www.pcguide.com/ts/x/boot/walk/hd1.htm
14. The system continues booting from the hard disk and the message "Starting MS-DOS" or "Starting Windows 95" is displayed
http://www.pcguide.com/ts/x/boot/walk/hd1os.htm
15. Operating System Loaded From Hard Disk. The system has found a boot sector on the hard disk and is now starting the load of the operating system. The hard disk is working. You have successfully completed the hardware part of the boot process. Any problems encountered after this point should be diagnosed by looking for a more specific problem with a component, or under the section that contains run-time error messages.

[penny]

Yipeeeeeeeeee, it's working. I'll tell you all what it was. At the begining I mentioned that on the keyboard, the Num lock, Caps lock and Scrool lock were on all the time. I changed the CMOS battery and the PC booted. It said on screen to press F1 or F2 to continue. I did but nothing happened. I had a spare Keyboard so I plugged it in and pressed the F2 key and it worked. Only thing is that now when Windows desktop comes on there is a message from Microsoft saying Send Error Report or Don't send. Well I can't send cause She is not on the internet. So I just have to keep clicking on Don't send until it goes. Probably have to put up with that. Many thanks to: Ski, Ravenwood, Sylvander, MJC and Whyzman.

[Sylvander]

Was the 1st keyboard USB and the 2nd PS2?

[penny]

It was a keyboard from a previous PC that I once had and had the same fitting.

[penny]

It is a round fitting like the mouse (not USB), and plugs into back of PC.

[penny]

Both keyboards are the same fitting.

[Whyzman]

Was the keyboard connector flat or round?

[penny]

Keyboard connectors are both round.