Ok I'll explain this simply and toss in a few tweeks
any and all onboard video uses your installed ram to run...
some of them are adjustable in the bios screen (hit del as the pc starts) look for the video ram alottment and toggle its settings
you ussually will see different settings for ram
AE 8mb 16mb 32mb 64mb
now remember that this will use AE 64mb's of your installed ram
so lets say that you have 256 mb's worth of ram
you have XP as an operating system
XP uses 128mb's of ram ussually
VC uses 64mb's of ram
this leaves you with 64mb's of ram left for loading games page files ect....
If you learn to tune xp to were its running the min required programs it may still not have enough ram to run AH2
