ive just put the preview release on my bruvs comp(he doesnt have the net) and every time you load a game up the game jumps about and the sound is ditorted can anyone help

if its any good to you he has got a amd athlon xp2700+ 2.16 ghz with 448mb ram
also has a realtek alc 650 sound card

please help as i would like him to be able to enjoy this wonderful game