For the last couple of days I've had a problem with Half Life 2 freezing and crashing the whole system. What happens is this:
For durations of 1-2 seconds the game will freeze (no movement or sound) with 1-2 second intervals. This will sometimes happen once and then I can play on, but will be followed shortly by another instance and a complete crash. I get no error message, just a blue screen (which doesn't quite fill the monitor) which won't go away until I restart. Occasionally on reboot the boot sequence stops at "Verifying DMI Pool Data". A hard reboot doesn't give this message.
I suspect overheating, but the fan on the card seems to be working. The card is pretty old, I'm considering looking for a replacement.