get some ram and tweak xp. or better yet, install gentoo from stage 2 (stage 1 no longer exists, and stage 2 gets hardly any love anymore, but its still around), or hell, go for the whole deal with LFS. only true way to bring the beast out.
btw tweaks do make a diff. i had this program once (sorry dont remember what it is anymore) that made my old desktop boot win xp faster (before tweak - 50s after tweak - 30s, it also made running programs in xp a sec faster... openoffice1.0 took 30 sec pre-tweak, about 20 post-tweak, and that was on a 233mhz pentium) so that helped. also kill the eye candy, that will speed you up. and don't forget to put a desktop picture of a ferarri, i heard it makes it faster too