Running Windows 10 under Bootcamp

My installation of Windows 10 has failed and it won't let me log in. I try to provide my pin number but no reaction from Windows.

So how do I get in to Windows to try and fix the problem.
As I said I'm running Bootcamp on a iMac running macOS Sierra v 10.12.6. Bootcamp will get me to the Windows 10 log in screen and no further.
Is it possible to do just a re-instal of W10 that leaves the files intact, or am I going to have to repartition and lose the lot.

If the latter Bootcamp assistant will allow me to remover the partition holding W10. Is this the way to go, and then reinstall W10 and the software from a backup?

peters

G'day and welcome to the forums.

Use BootCamp to remove the partition or you wil lbe in deep strife. When you mention your p[innumber, do you actually mean the activation code for Windows 10?

If you have Windows 10 installed elsewhere,you may well need another original copy as Microsoft does not like more than one activation of the code from when I used BootCamp. I found the best solution was to run Windows 10 from a cheap Dell latitude laptop.