What games can I play?

[arnoreids]

ACE Battle 4 500W powersupply
CPU AMD AM3 Sempron 140 2.7GHz 45nm 512K
MSI K9N6PGM2-V2 - MCP61, 2xSATA2, 2xDDR2 800
RAM 2GB DDR2 from Corsair
Hard disk 320GB WD Blue - SATA II 300MB/s, 7200RPM, 16MB buffer
512MB MSI Geforce8 NX8400GS - DVI - HDTV - HDMI - PCI-E 16X

 

[dndhatcher]

http://www.tomshardware.com/reviews/geforce-310-5970,2491-7.html
You can see that the 8400 is way down on the chart, even below the onboard graphics alot of motherboards have. Its not designed to run games.

It should play flash games and such, but is not likely to play any heavy games like COD or MMOs like WoW even at minimal settings and low resolutions.

Something like an ATI 4650 or 4670 should let you play most games reasonably well at low resolutions. If you want to play the latest games on newer HD LCDs you would need a new computer and expensive gaming card to have a good experience.