well,there area few steps you need to do,,,first reload all your direct x,,,reload your vid card drivers,,,and check your sound card,,,,,do you have a old sound card?,,turtle beach montago?,,,seems like your computer is old anuff to have one,,,my buddies computer had the same problem,,he couldnt play more than a few seconts with out it locking up,,,because his sound card has a c-media chip on it<~~and it will cause aces high to lock up and random,,and loss of sound,,,,after we replaced it,,,had no troubles,no more lock ups
and you mite have to bite a bullet and get a new vid card,,voodoo's are not suported anymore and will give you more trouble than its worth