Need upgrade advice for Gateway 830GM

[shastamike]

I need a faster computer and have upgraded everything but the CPU. Do you have any advice on Motherboard/CPU combos?
I now have
Gateway 830GM case
power supply ? more that 350 watts
D915GAG motherboard 800HZ front bus
Pen 4, 3GHZ
Nvidia 8600gt graphics PCI
I'm not sure what will fit my case and power supply. I would like to stay under $500 and stay with Intel CPUs
I edit a lot of large photo files and some video. I'm a casual gamer. Thank you for any advice.

 

[groo]

get a decent Antec PSU in a new case. about $100.
then get a C2Quad s775 based system with the other $400.