Your CPU and RAM are perfect for gaming. The MX400 will give you average gameplay but only in low settings. You might want to consider upgrading it to at least a 64MB card.

Newegg.com has a GeForce4 MX440SE 64MB card for 53 bucks.

Aopen Geforce4 MX440SE 64mb with TV-Out - Retail Box
Specifications:
GPU: Nvidia Geforce4 MX 440SE
Memory: 64MB 128-bit SDRAM
AGP 4X w/ Fast Write
Support Dual, Independent Digital Vibrance Engines
Support 34 Million Triangles/sec (T&L) and 1.1 Billion Texels/sec
Ports: VGA 15 Pin and S-video Out
53.00

http://www.newegg.com/app/ViewProduc...tby=14&order=1