Computer advice please

[Jinx999]

The computer appears to always be doing something when it occurs, but not under particularily heavy loads.

[Jinx999]

Last error I tried using the integrated graphics (which the previous and sadly maligned motherboard didn't have) - no output. Which is what you get when it's normal

And the computer makes a sound when I unplug the monitor when it's running normally, which did not occur during this error. So it's not just the display that goes.

[Jinx999]

Based on the way it's the display that goes funny whenever my computer crashes, I've decided to take the card out and use the onboard display adaptor and see if that helps.

[bmull]

It could be the ram on the video card going bad.  I had a video card years ago where the memory started going bad and I was getting symptoms like you listed.  I just ended up replacing the card and everything worked fine.

[Jinx999]

I've heard of things like that when searching on the internet. The problem is that they all seemed to be having lines on an otherwise normal screen, not nothing but lines on a dark screen.

[bmull]

I've heard of things like that when searching on the internet. The problem is that they all seemed to be having lines on an otherwise normal screen, not nothing but lines on a dark screen.

Nope, this one did not have lines all the time.  It did happen after the card had been run for a while so it was also thermally related.