As I said I run out of OS paged pool mem. My specs are as follows:

Dell Optiplex GX270
2.7 GHz P4
1 gig RAM
GeForce 5500 FX
and the motherboard was recently fixed
and i ommited sound card cause i dont have one

Now if I play a recent Source game (which is TF2, HL2 ep2, but Portal never gives me trouble) it can crash and says out of OS paged pool memory. Sometimes though it crashes completely and my comp freezes. If it is an earlier source game, it does both of the above, but for the game only crash it instead says "error with IDirect3d device," or "*arbitrary address* requested data at *arbitrary address.* Memory could not be "read."" And yes read is actually in brackets. I have asked peopel on this matter and they always give me different advice, so im am looking for a concrete answer. Hope someone here can give me one.

Update your graphic drivers.