If you run it and you have antivirus definitions on the computer you are scanning, you can point them to those definitions. Same might be true if you download definitions to a thumb drive and have it in the USB port when you load the SERT. I have seem some guys talk about bustin open the ISO, replacing files, and then recompiling the ISO, but I am not sure I want to go through all of that. If you copy the definitions from a working computers to the hard drive of the one you are scanning, you can just use those.