Need help restoring computer

i recently installed nortons systemworks pemeir and i restared my computer and it just stays on the booting screen for a long time and doesnt go to the profile select screen. i went to safe mode and tried to uninstall the program but it wouldnt let me it said i had to be in normal mode to unstall it. well i did system restore and the same thing is still happening. btw the program was downloaded using bittorent. then i selected last known good configurations and it said that a file was missing and it shut down my computer. my question is can i use my windows xp home edition cd to install missing files on my computer. will this erase all my documents on my pc to ike new cuz i dont wanna lose anythin that i have on my computer?