Some will break down and call up Microsoft to pay up for recovery of the OS. Last time it ran 140 US bucks so count on that much.

Here we handle this from time to time but very few will sign up for the 6 hour up front bill so they opt for the cheap exit. Here it is. We slip in a new blank drive and install the OS to that. The old drive goes into some USB case so they can access the files they didn't backup.
Bob