Lee still uses Windows XP and it keeps installing the Microsoft Malicious Software Removal Tool even though it's already been installed. Leo says it's normal for the MSRT to be updated every month. That's the idea.
Would Windows 7 run most of the programs that Lee uses in XP? Leo says yes, unless it's been abandoned by the author. Windows 7 Pro has a great compatibility mode for just that. So upgrading to Windows 7 is a good idea. And he should always remember to run as a limited user.