CPU and more memory will help most. The graphics card is not an issue. Need to know make/model of your psu, and whether you have an original Windows disk or not. If no disk (or a "recovery disk"), you can't change mobo and cpu without buying a new copy of Windows.
The Q9550 should provide results like this (find Photoshop):
About 10% improvement vs the Q9550, without factoring in any improvement for additional memory which on its own could be substantial. Plus you get a modern platform. You can evaluate whether the extra money is available and worth it to you. Will provide specific parts if you wish to take a closer look.
Sounds reasonable. Think again about the memory - even losing nearly a gig due to OS, your concern should be how much speed does a LARGE percentage increase in available memory (2GB - OS use vs 3GB - OS use) generate?
Sorry I can't answer it for you. You might recerve more memory for a second step if needed.
I have 2 megs ram for winxp - increasing to 4 only gives me 3 only addressable - ? value there
A valid point. You could just get another 2x512GB RAM for a total of 3GB rather than spend double for a 2x1GB kit that would give you ~3.3-3.5GB usable RAM on 32-bit. If you plan to stay 32-bit that is.
on the other hand my board revision *supported* quads (NOTE: Q6xxx only), it would not run solid on cold starts - not sure if its my board or the series with that fault so i just replaced it etc
For now xp 32 bit - New platform in a year or two 64 bit . Just too much pain to reinstall OS and all of the software. I fondly remember when an OS install did not force reinstallation of everything. I sort of hate the registry (end of rant). I'll look into a 9300 and a meg of additonal ram and wait a year or so for the next platform. I think for now that may well be my sweet spot.