Checkerboard video on bootup

I think my video card is giving out or has given out. When I tried to boot my computer today it immediately displayed a checkerboard like pattern all over the screen and I can't make anything out. It happened yesterday too, but I just restarted the PC and it worked. I was even able to play L4D. I had only previously noticed this in games recently, but I guess the problem has progressed.

The system (see sig, I think the CPU is upgraded though) is pretty old. Is my video card just calling it quits? Is there a quick/easy fix for this or should I just spend 20-40 bucks on an AGP card from the classifieds? I'm about to build an i7 rig, so I don't really need the old PC anymore, but I'd hate to see it become unusable.

For quick an easy pull that card and make sure it is clean by not having a ton of dust covering the air holes. Make sure the fan is still working. But back in and make sure it is seated correctly and see if that helps. It could just be overheating.

+1 on above and just to add..
Maybe remove the hs/fan assembly and replace the thermal conductive material/paste on the gpu, not the memory ic's though. They probably use a thicker material, be careful not to lose those pads.

Checkered video on startup: check and if needed, replace the 4.5v battery in the back of Macintosh 512k.

Oops wrong era...