If you want a XP tweaking tool, use TWEAKXP. It works well enough, though some think its a waste of space. I have noticed a speed increase.

Also, if you have an intel MOBO, you could try the Intel Application Accelerator. Works wonderfully well.

And for a hardware based approach, 3 things are key to a fast system, well 4 but the last one can be sacrificed...

CPU (at least a 1.0ghz)
MEMORY ( the more the merrier)
VIDEO (geforce 2, preferably, geforce 3 or better)
HDD 7200RPM, with at least a 2MB buffer

Hope that helps.
BB