I imagine your running XP /OS judging by the 1 gig of ram? I recently had an issue with XP-home, after researching I found that my problem was due to video open-GL. The long lines of rendering were too big for the zbuffer, they have upgrade patches for windows and issue resolution tips on the Micrsoft site. Yeah my system would render most of an image, but towards the end when the calculations became too much it would just freeze. The reason I thought it was weird was during a normal crash windows would post an error or reboot with a scandisk OP. Not this, it would reboot like nothing happened. Seems ok now. Hope this helps, Good Luck.