As I stated in my previous post about NanoScan it can only report malware infections it finds in your computer's memory. So if your computer is infected with malware, then you have to use something more sophisticated. So if NanoScan finds a problem, it will automatically direct you to TotalScan (its free, but requires registration).
TotalScan can detect more malware then NanoScan, plus it can remove what it finds. TotalScan has two options, Quick scan which only takes a few minutes to run and Full scan which can take more then an hour depending on the amount of files on your system.
So for those times you need to run deeper scans of your system, I would suggest that you check out TotalScan. Like NanoScan it runs in either browser Firefox or Internet Explorer. It also does take a few minutes for the signatures to download (depending on the speed of your connection).