problems with Microsoft Games

[kitnphan]

I am having this unique problem

I have recently assembled a PC with 915GVWB motherboard, 512 MB ram, 80 GB HDD, 3.0 GHZ PIV, etc

I have installed XP prof. with sp2 and have not installed any other cards but using on board video and audio only.

When I am playing Microsoft Games like Age of Mythology/Titans and Age of Empires III, I am having a unique problem, after playing for some time, the game closes by itself and some times it gives error message, and some times nothing.

but when I play other games like Warcraft III, GTA III, GTA San Andreas, there is absolutely no problem and working fine

what might be the problem?

There is one more problem, my motherboard doesnt have any AGP slot and PCI-e slot is smaller one, (X1), so I cant install any extra 3D card, because only 2 pci slots are there.

Any suggestions?

[CyCo]

specify the error which comes somtimes ...