Hi

I have a system that has been working fine for over a year. Now, suddenly, on booting it says I have an 'Invalid System Disk'. This suggest problems with the hard drive, but it won't boot from a bootable floppy, nor from a bootable CD-ROM in either the CD-ROM drive or the DVD drive either.

In each case, the BIOS is correctly set up to allow the relevant drive to be treated as the bootable drive, I have checked the floppy and the CD-ROM concerned are bootable on another PC and I have checked all the relevant connections inside the PC.

HDD: whirs twice, more noisily than usual, then says "Invalid System Disk"

FDD: system says it is booting from FDD, FDD light comes on, FDD makes the noises it would make if it was going to boot successfully for a few seconds, then stops, FDD light still on, nothing has been added to the message saying that it is booting from the FDD and system locks up. The only way to reboot the PC from this is to turn it off.

CD-ROM: system says it is booting from CD-ROM drive, CDR light comes on, CD whirs a bit then stops, CDR light goes off, nothing has been added to the message saying that it is booting from the FDD and system locks up. The only way to reboot the PC from this is to turn it off.

I could believe it was a HDD failure, but then why wouldn't the system boot from the FDD or CD-ROM? I'm baffled (as is the manufacturer so far) and wondering if anyone has any suggestions.

Many thanks

Steven

Suspect a bad motherboard. Perhaps a shop can test it.

Hello,

First, if it is still under warranty, get it serviced under the warranty. If the warranty has expired, then open it up and take out everything except the HDD, one stick of memory and the video card and the keyboard. If you have a spare known good vidio card available that would be nice. If it won't boot up then swap out the video card. If still no luck, then swap out the RAM, if still no luck, swap out the HDD.
If nothing works, then it may be time to reset the BIOS. If reseting the BIOS does not work, it may be time foe a new Motherboard. Oh, one last thing to check is the power supply......if you know how! If you don't know how, find somebody that does! Don't get somebody who "thinks" he can......get somebody who absolutly knows how!

Good Luck
Steve

Hello Steven

Could you have a boot sector virus or one of those that alters your CMOS settings so that your drives aren't recognised?

I did some reading on the topic and sent you some info by Email but it's not a subject I know much about.

Perhaps someone out there knows about these types of virus?

I too was suspecting a virus.....but if it is preventing booting from any media I am kind of stuck as to how to get you out of this mess....


Try unplugging th hard drive and setting the boot order to floppy first then try booting to a floppy.

Also try reloading the default values for the BIOS, that should retrun you to a basic setup.

If you can get to booting from a floppy, then on a known clean machine make a bootdisk, write protect it (move the little tab), then reconnect the hard drive and try booting to the new boot disk...if you get that far then type fdisk_/mbr (a sapce instead of the underscore). Also an emergency repair disk from a virus scanner (also write protected) would be something to run next...

------------------
mjc
Links list:Computer Links (http://www.dreamwater.org/tech/mjc/index.htm)

Celts are the men that heaven made mad, For all their battles are merry and their songs are all sad.

Hi everyone

Thank you all for taking the trouble to reply.

I can't be sure of course (you never can be!), but I don't think it is a virus problem, because I have Norton AntiVirus and a firewall on my system, the virus definitions were completely up to date (downloaded that day followed by a full system scan of all files, not just program files) and in any case, I hadn't recently downloaded anything other than emails, none of which were suspicious.

I had already tried booting from a Windows Setup floppy previously produced on the same machine, from an emergency repair floppy previously produced using Norton AV and from the manufacturers emergency boot CD-ROM, but to no avail. I had even tried disconnecting the HDD and booting from the floppy. In each case, the boot order in the bios was set appropriately.

The PC is under warranty (one year and one month old, so I'm glad I extended it to 3 years onsite!) and the engineer is coming on Friday so we'll see what happens then, and I will let you know on this thread.

In the meantime, it's probably best not to try the more drastic suggestions, though if you think of anything else which doesn't involve taking the PC apart too much, do let me know!

I posted the query on here in the hope that either it would allow me to get things back up and running more quickly or, failing that, it might generate a list of things I need to make sure the engineer tries before he gives up. Some engineers are excellent (in which case I breathe a sigh of relief and let them do their stuff), but sometimes you get one who isn't too great or simply can't be bothered, so it helps to have some guidance in advance in case they need to be nudged in the right direction, and this you have certainly provided in abundance.

Thanks again

Steven

Hi everyone

I promised to update you, so ...

The engineer came on Friday, decided it was a motherboard problem, replaced that ... no change.

Changed the hard disk ... no change.

Then he changed the CPU itself and at last, it worked.

He left the new HDD in because of the bad sectors in the old one but the old one was still functioning once the CPU was replaced so he gave me 10 minutes with it connected as a slave drive to the new one to get off anything that would have been a real pain to retrieve from backups.

I'm not sure if that leaves us any the wiser as to the exact cause, though obviously it was a failure in the CPU. Still, with a new CPU, motherboard and HDD, I've almost got a brand new PC, so it could be worse!

Thanks for your help anyway

Steven