yea if you just reinstalled system restore wont do any good. but ti does bring back an old copy of the registry, in the future you access it by start>programs>accessories>system tools>system restore.
after you reinstalled did it change all the windows xp settigns to factory default? or does it appear to be using an old copy of the registry and still using your old settings? if the install went correctly then it should have put in a new regisrty. if not you can this
http://support.microsoft.com/default...&Product=winxp