Microsoft Sidewinder Precision 2 Static What Is A Good CPU And Motherboard Upgrade?

What is a good CPU and Motherboard upgrade? - microsoft sidewinder precision 2 static

I kinda need advice on my computer, can someone tell me if my installation is decent? I play many games like COD4 and CS: S and I think that another update may be necessary. I think my CPU is a bottleneck for my 8800GT I bought recently. I thought it would be more help than my Radeon X300, but I have seen it increase to. If I have a dual-core or multi, I would buy a different motherboard, not because of supporting the current dual-core CPU. A little irrogant father because he thinks he is right now, but I know that the Pentium 4 can not handle today's games. So I have a very good CPU and happiness is not a motherboard. I spend some $, but I can not buy the whole 9 meters. Suggestions?
Today: HP Media Center PC, bought in 2004. (* It came with the PC)

Windows XP Media Center Edition *
2.8 GHz Intel Pentium 4 Prescott
2.5 GB PC3200
512 (i think maybe a Lil) XFX Nvidia 8800GT XXX Alpha Dog Edition
ASUS Mobo buffer *
WD Caviar 150GB HD *
Realtek sound Intregated *
Microsoft SidewINDER Precision Cycling
22 'Acer Monitor