Happy you're back in action
I fear my GeForce 8600GT is heading the same way. 'Heavy' games keeps on randomly crashing. Sometimes Windows just reboots when I play graphic intensive games, like 'Race Driver:GRID'. Typical signs that somethings getting a bit too hot.
The card originally had no fan, so I've put one on the GFX card, and it helped for a while - just ain't enough anymore.
So I'm currently looking for a replacement.