Firstly, let me explain that I don't actually know what part of my PC is failing here, so I'm posting in the section of the forums where the failure is most obviously seen :)

Secondly, my specs (to the best of my knowledge). If you need anything else, just ask :) The PC itself is about 3-4 years old.

OS: Windows 2000
Processor: Athlon 1Gig Hz
RAM: 512 SDRAM
Video Card: ATI Radeon 9200 (dual 64/128MB)
Motherboard: ISA AGP PCI USB i2c/SMBus
System Bios: American Megatrends Inc. 62710

Thirdly, I did replace the video card at Christmas (it was previously a GeForce 32MG), but the problems started about 3-4 months after this. Also, the PSU has been playing up for some time - there was an issue a year back where it was overheating. The PSU does seem to be fine for the moment, and these new cut-offs are entirely different to the complete shut-down's the overheating caused. The hard drive has also been replaced, but this was last year.

Okay, now for the problem I've been having.

It doesn't happen every time I use the PC, but seems to be growing in frequency. After about 3-5 hours of use, which is mostly browsing the Internet and talking to friends, the monitor sudenly cuts out.

The monitor still has power, as the green 'on' light has changed to orange; as if the monitor had gone to a standby. If I turn the monitor off and back on, it flashes a 'No Signal' message as if it wasn't connected to the PC properly.

The PC itself is still running (green light on, hard disk light occasionally flashing) and is utterly unresponsive. I can't shut the PC down by hitting the Windows button and then 'U', for example. It has to be shut off manually.

Turning the PC back on immediately after the crash has 1 of three outcomes:

1) The monitor remains 'on standby' and cut off.
2) Picture returns, though the boot up is unusually slow. Part way through load up, it either freezes or the monitor cuts off.
3) The PC manages to load up completely, along with all applications. After about 5 minutes of use, the screen cuts out again.

So far, I've found one consistent way to turn the PC back on and get it to say on; and it seems entirely unrelated to the problem. I have to disconnect the Internet (is a network cable leading to a router for broadband Internet) and leave it off for a long period of time. Then when the PC has fully loaded up, I can reconnect the Internet and carry on working with no problems. If I turn the PC on sooner, or don't disconnect the Internet, it won't load at all.

I have a feeling that the cut offs are connected with my failing PSU and my very old and underpowered motherboard - but I'm not certain about that at all, as my PC knowledge is quite limited. I don't think it's a problem with the monitor, as that has worked flawlessly for the last 4 years. Nor the graphics card, as surely it would have failed soon after reinstalling and not the 3 months later? But then, I don't know.

Does anyone here have any ideas as to what is going on?

Hello Silverskeejee,

Welcome tohttp://www.pcguide.com/ubb/pcgubb.gif Forums!

The problems you describe definitely sound to me like PSU/Heat related...

The fact that you can get back to some normality after allowing things to cool down points my thoughts in that direction...

My first question would be regarding "housecleaning" of your computer. Do you have a "deferred maintenance" situation with the internals of your computer? Do you routinely blow dust and accumulated crud out of your computer's innards? And also the PSU?

It could be, as you suspected, that the PSU is being overtaxed. A system 3-4 years old was probably marginally powered at best on the 12V leg and your video card is probably feeding at the 12V trough like there's no tomorrow.

You might want to have a look at the electrical requirements of your current set up and see how things measure up to the 3-4 year old diet your system is currently dishing out...

http://www.firingsquad.com/guides/power_supply/default.asp

Eh heh heh...that's true, I don't really clean out my PC's innards very much (read - don't think I've ever done it in memory...) Any idea on the best way to do that? I hate messing around with my PC's guts, heh.

Many electronics stores or some of the more well known department type stores like Wal-mart sell cans of compressed air designed for cleaning electronic components...

If there's a lot of dust, etc. in your PSU that would not bode well for its health...heat is an electronic components nemesis...;)

(edit) Or, for that matter, the heatsinks fins surely don't appreciate restricted heat transfer...

Okay, thanks :) I'll keep an eye out for those compressed air cans - they should sell them somewhere in the UK :P I'll also see what I can do about the PSU - the store I bought it for isn't far, they should at least be able to do something with the thing ^_^

Oh, and thanks for the welcome :)

The 9200 does not have a cooling fan.
BUT the heatsink needs to be clean.
More over it should have a lot of air flow across the heatsink.

In most cases the best idea is to leave the slot next to it empty or install a fan to move air across or a least blow toward the slots

If you have a tower case. and it sits on the floor ( especially if the floor is carpeted )
You need to keep the tower up out of the carpet and clean out the inlet holes