I have a hp pavilion a335w. It a has p4 @ 2.5 ghz and somthing like a 478 pin? I want to keep the processor. And I want to upgrade the motherboard to somthing with a agp slot. I plan on getting an ati 9800 pro when done with mobo swap. Any help and info on how to do this and what kind of motherboard to get would be greatly appreciated.
If you buy a new case, your life could be made mch easier.
IIRC, most HP's use realtively stock mATX motherboards, so almost any retail Micro ATX board should work. But since I don't know exactly what your computer has or needs, I can't give good advice.
You also may need a new copy of Windows, since IIRC, HP's quick restore looks for an HP motherboard before it installs.