I reformatted my cousin's desktop with Windows XP SP3 because apparently she doesn't maintain her PC from viruses and malwares. Avast scanned through 3000+ viruses so we decided to reformat. But the problem is that after we installed everything, we can't log in because the damn PC is asking for a password that I didn't suffice. Any of guys can give me hand to solve this? Any kind of help would be appreciated.