the easiest way for us to help diagnose pc problems is for us to see its dxdiag file . ( Start / run/ type in dxdiag ) let run then save .
i recomend not letting it look for signatures as for alot of drivers are not regestured with microsoft.
post up the 1st 1/4 - 1/3rd of the dxdiag file and that will help us to help you .
otherwise were just guessing in the dark ...
min specs for AH2 is 800 mhz , gf 2/4 grafics card , 256 ram
even that is pritty weak to really enjoy the game.