This is similar to how I used to clean computers that data was needed from. I would isolate it for a few days (no power on, disconnected from any network, etc)

This is similar to how I used to clean computers that data was needed from. I would isolate it for a few days (no power on, disconnected from any network, etc). Then use a burned DVD or USB with MSFT's Offline Defender. The extra few days really seemed to help the definitions catch up with whatever had infected the system in the first place. I do not believe Offline Defender can do this anymore, so this exact approach is probably no longer doable. I also do not do family IT anymore, so I have not had to do this since Win7's heyday.