I'm getting exactly the same problem, Ross, and have been for a couple of months now, so I can't attribute it to being a heat problem.
I thought it was Microsoft keyboard software (as this showed an error in the system logs immediately following a lock-up). I uninstalled that and the problem seemed to have gone away, but in the last couple of weeks its started doing it again.
It could be memory (I have 3x512Mb), or it could be a motherboard problem (XFX KT600ALX I think?). I might whip out two of the RAM sticks and run it for a few weeks, see what happens. If I still get crash problems then I'll probably replace the motherboard... although I dunno if Socket A mobos are still available so it could get quite expensive... :/
I thought it was Microsoft keyboard software (as this showed an error in the system logs immediately following a lock-up). I uninstalled that and the problem seemed to have gone away, but in the last couple of weeks its started doing it again.
It could be memory (I have 3x512Mb), or it could be a motherboard problem (XFX KT600ALX I think?). I might whip out two of the RAM sticks and run it for a few weeks, see what happens. If I still get crash problems then I'll probably replace the motherboard... although I dunno if Socket A mobos are still available so it could get quite expensive... :/