Right, it does beg the question - Is he addressing the cause, or a symptom of a much larger issue that led him down the path to needing to edit the registry in the first place.
The reg file TXT should in theory fix the EXE association in Windows 7. But that doesn't mean there aren't other pre-existing problems that also need to be resolved. In which case, yeah, an OS reinstall might be required.
He did post this under the Windows 7 forum. Hence why I mentioned it.
Anyways, he did ask for advice. If he's going to reload the OS anyways, I don't see the problem in at least making a best effort at fixing the issue. Honestly, I give it 50/50 chance. I've personally seen Malware whack EXE associations, so fixing it would probably be a futile effort in the end if that's the case.