We run games like Sims 2, BFME 2 etc.
The question is whether it makes more sense to start again, or say chuck 2gb ram in and a half decent AGP graphics card. (has a 120gb modernish hdd, and running XP sp2) Its a bit noisy but can live with that.
My feeling is that the CPU speed is not that important, but the graphics is. The mb would support anything faster than the cpu already in it which runs at just over 2 ghz.
I guess upgrade for $500 or new for say $1500, but its also bangs for bucks.