The reason for this instruction is that a threat usually exists beyond the virus, worm, or Trojan itself. Information Security Office (UISO) will instruct you to reformat your hard drive (erase Windows) and reinstall Windows from scratch, even if your antivirus program or other antiviral tools can remove the virus or delete the infection. Why you should reformat your hard drive and reinstall Windows after your computer is infected with a virusįor many virus, worm, or Trojan computer infections, the