Yesterday I had my Nvidia driver crash on me 3 times within an hour. (seriously last time I ever buy a Nvidia GPU)
I decided I wanted to update them to the latest beta drivers, which are 3 points ahead and seem to promise up to 60% increased performance on some games.
But of course, Nvidia crashed during install. breaking Windows. Windows won't start because winload.exe is missing/broken. Startup repair wont fix this. And somehow I was not able to access my secondary Windows install.
So I had to reinstall, tried Refresh. But got the notification "Can't refresh, please unlock hdd"... wtf?
It's not a floppy disk with a trigger that tells the system its writable or not
But anywho, I still have an USB with the Win8 setup laying around so no big worry, I'll go the old fashioned way.
"Previous Windows files wil be put in Windows.old" okay, sounds familiar, at least I keep my data..
All windows 8 saves is users folder, program files and the windows folder get deleted.
I didn't know, and this is how Windows installs have worked since at least XP, now it changed without notice... nice.
TL;DR If you reinstall Windows 8 through the setup, you will lose everything except your user folder (and cusom folder), program files, windows etc are all deleted.