Re: Repair OS
If time permits then I typically always nuke the drive before installing Windows again. I wouldn't say it's made its way to "Rule of Thumb" status, but in my IT Department, if we have to clean up a PC for whatever reason, I always have my guys nuke the drive first. It's probably not needed even half the time, but the time spent up front will save a lot of headache in the event that scenario comes true.
Again, it's not a rule of thumb, per se, but I always do when I have a faulty Windows installation.
If you've already reinstalled and are in the process of updating, then hopefully there's no lingering issues. (Updates (IME) are the first to show signs of faulty kernel files).
Humans are the only creatures that won't live up to the their potential. Give everything your all. When you die, die on E.
So I ask you, what do you intend to do now?