freezing all the time, and i mean ALL the tme!

[aardvark]

i love this game but i can only play so long until the scren freezes and i have to hard reset my pc. It doesn't happen at a fixed time (could be after an hour if i'm lucky, sometimes after 1 minute!) and it doesn't happen after any one event (seems random as far as i can tell) - but it can happen several times a night until i get bored of reseting.
i have all the latest drivers (on an 8800gt) and this doesn't happen in any other game - nothing shows up in the event viewer and i can't find an error log anywhere so i am at a loss to explain it or solve it. i installed the russian 1.64 patch but that didn't help.
does anyone have any ideas? if it wasn't such an addictive game i would have given up ages ago!