Help With HL2DM

[opgspwnage]

Hi, im having some probs with HL2DM. i bought the game of the year edition of css. Everything runs perfect except HL2DM. after a couple of mins of logging on to a server the game just crashes, usually ending in me just having to reboot. it worked on my old comp which hardly even met the specs. i am running:
windows xp media centre
dual pentium d's ~ 2.4GHZ
ATI radeon X600 256mb hypermemory
1024mb RAM

any suggestions?

Ty