Suggestion for replacement parts

[jman123]

I was hoping you guys could give me suggestions on which parts would be good to replace my motherboard, CPU, video card, and memory. I am not looking for the fastest computer, I would like something reliable and that I could play games on if i wanted to. Because my last computer I had trouble when the computer went into 3-D.

I am assuming my older parts would be fine with the suggested replacements, however I listed them anyways.
My Pc Components are:
PNY Geforce 8800 GTX
Intel Desktop Board D975XBX2
Ultra X3 800 wat ATX Power Supply
intel core 2 quad processor: 2.4 GHz, 3.25 GB of Ram
Microsoft XP professional 2002