Things are clearer thanks to you. We are always at the mercy of the Software Engineers; I know exactly what you are saying about installing those programs you mentioned. It is always best to do a back up when working on a system, you never know what could go wrong but performing a Repair Install is safe, it will allow you to maintain settings, data and all applications including the ones that have problems, Repair Install Repairs XP which might or might not affect other programs with problems. You will have to re-install all Windows update you had already installed. Many "Software Optional" updates available through Manual Custom Update are necessary for Windows to operate properly. 2 teenage daughters with MSN, Face Book, P2P programs and such does sound like "trouble", I know many with no problems at all. If the programs you used were already installed before the infection if any, the chances are they were compromised; In such cases, I load Windows in Safe Mode, log in as Administrator, perform some manual cleaning, use some cleaning programs then uninstall MBAM and SAS, run the cleaning programs, re-install (I always have the latest setup + the latest updates on a thumb drive) then do a quick scan with each first and run the cleaning programs again, still, this practice does not guarantee a clean system. Just trying to make a point that running the programs you mentioned in "regular" Windows on a possibly infected system giving you a clean bill of health would not surprise me.