[John Galt's cousin]

Could he take the hard drive out and install it into another computer (that has all antivirus and anti malware up to date), find and copy “My Documents” etc, reformat the failing drive, then install into “old” box and then reinstall windows?

Or just but a new disk drive install windows and then antivirus and antimalware and then search for my Docs ??

[Bloody Sam Roberts]

Could he take the hard drive out and install it into another computer

Yes...I have done that in order to get data from one in such condition. It ought to work. But as a boot drive...it's toast.