Crypto Software causes computer to crash

[SoCalRugger]

Whenever I play on a Crytpo site, everything runs smooth for the first hour and a half or so. But after about this much time, it inevitably causes my computer to restart out of the blue. The only other program I'm running at the same time is Cryptocounter. My computer handles Absolute software just fine, and I can play the Crypto casinos for hours clearing bonuses with no restart. Computer is about a year old, but pretty good. 512 MB RAM, 3 GHz Pentium 4 processor.

Any ideas? It's happened about five times so far clearing June and July bonuses. It never hurt me bad until tonight, where I had TT on one table about to see the flop heads up, and A6 in the big blind on another table where the flop was AK6. I just about sent my mouse through one of my monitors, so any advice to prevent this would be appreciated.