This all started yesterday when I tried opening Photoshop CS4, which I've been running for years.
First it began to load OK but very quickly sent my display into 640x480 which nothing except a reboot seemed to fix. I tried again, and exactly the same problem occured - no other programs would repeat the error.
I thought it may be a display driver issue (although Device Manager reported no issues), so I updated my GFX card (an ATI Radeon) drivers, which promptly made only part of the desktop visible, causing it to scroll whenever the mouse neared the edges.
I then tried a System Restore to about 2 days prior, and that's when Windows failed to boot up at all. It goes through the initial stages, but restarts just before the part where I'd normally log-on (i.e. when the GFX card has to kick-in).
My hunch is that the card has died, but I'd like to eliminiate other possibilities first, as I'm not exactly swimming in cash ATM - but I've little clue where to start.
Edit: I'm running Windows XP SP3