Nice to see all of you helping this guy here
. First try getting the latest drivers for your videocard, perhaps even the latest patches for this game. Set the graphics to medium and try again.
Also try this: Start>configurationmenu>system>advanced>settings>advanced>virtual memory (Windows XP, dutch version, yours maybe somewhat different). Set it atleast 1 gig above recommended.
Since Kami claims he is the uber registry cleaner here he'll probably be nice enough to post a link for that(i lost them)