It was because I had to clean a computer it had around 8-10 vira, 8-10 trojans and a bunch of spyware. So Since it was on NTFS I first ran 2 different online scans, then I could install one antivirus program, the I uninstalled it and then tried another and got it reduced to 3 trojans, then I ran Spybot S&D and Spywareblaster and finally CWShreder to get rid of the last trojans. It took around 4 hours, and it would have been way faster if I could just boot in DOS and remove all the vira, and then remove the trojans and spyware from within windows.
Oh and I did instruct the person how to avoid these critters
