No, that isn't possible.
Viruses can be in the Windows folder and in the subfolders of Program Files that are filled during a Windows installation. And you can't remove all non-Microsoft things from the registry either.
Kees
I wish to use our old computer for a minecraft server, but it is virus-ridden and slow to the point that not even a boot scan with Avast and many hours of cleaning out programs is enough.
I want to get rid of everything but the OS. Everything. Unfortunately, we don't seem to have any sort of re-install or recovery disc to use. Is there any way I can bring the computer back to nothing but OS even without a disc?
Note that it is running Windows XP.

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