Registry/program issue

Hello, i need help.
i used advanced uninstaller to rid my cpu of nasties. and wound up deleting some registries. now when i boot up i cant access my system folder when i click on a program nothing happens. i even tried re-install xp Nothing happens the screen just stares at me. i have no clue on what to do. help me! Please Thank you.
p.s. i read up on my situation and regedit.exe dosen't work regscan/restore dosen't work im lost