Help! PC problem

[von Manstein]

I have problem and I don't know with what: PC or CS (or both). When I lunch CS after few moves game just freeze (sometimes during replay) and after 20-30 seconds whole PC just freeze. HDD's control light is on (not flashing) and nothing happens. Only reset button helps. I've get my PC back after 18 months and I remember that it happened few times before but it was seldom. Now it’s 2-4 times in a row.

I have Vista 64-bit.

Any ideas what it can be?

I've lost few very good artillery fire results because I had to restart game.
And by the way, I’ve notice that second time, arty fire is much worse than by first time and third and fourth time is the same as second :)

By this “scientific research” I’ve proved that it does not make sense to cheat!!! at least by trying to open game one more time