XP General is not a "Tweaking" type of Newsgroup.
The Internet has all kinds of Tweak and Tuning sites dedicated
to "Squeezing" extra performance out of XP(?). No two systems
will be the same in regards to performance tuning. Many folks in
General will counsel to not undertake any types of tweaking.
The best advice I can offer is go slowly & by all means have a
Image backup of your System partition. Tweaks can be detrimental
if applied without knowing the effects.
There are different criteria to tweak for Gaming, Multimedia &
other types of PC use and not all are effective. Actually, tweaking
is like Registry editing - Knowing when to stop is the key. Also,
some recommended Tweaks are just plain wrong or Urban legends,
so don't assume that anything you find on a web page is worthwhile.
Just take some time to research and read up on things, but keep in
mind that overall you aren't going to improve things dramatically.
The best place to start is search Microsoft's Knowledge Base with
the search string "Tweaking XP", as below
http://search.microsoft.com/search/results.aspx?st=b&na=88&View=en-us&qu=Tweaking+XP