Every great operating system sputters, falters and fails at one time or another, and Windows 10 is no exception. Whether caused by a Windows Update snag or a good app installation gone bad, you'll probably need to take some substantial steps to fix the OS at some point.
For example, after allowing Microsoft to automatically upgrade Windows 8.1 to Windows 10 on one of our office computers, the PC hummed along just fine for nearly a month before the cracks began to show. That's when the Microsoft Office applications stopped working properly. They crashed frequently, and Windows offered recovery versions of productivity files during nearly every computing session. Uninstalling and reinstalling the applications didn't seem to make a difference. We also noticed a rash of minor annoyances that went away, temporarily, only after rebooting. Then one day the Start menu became inaccessible and Windows 10 displayed this message:
Crucial error: Start Menu and Cortana aren't working
That was the death knell for the current installation of Windows 10. Although several websites offered step-by-step instructions for fixing the problem, none of the solutions worked for this PC and we were left with a machine that barely functioned. Any time we clicked the Start button, which happened a lot owing to force of habit, we had to reboot. Thus, it was time to take recovery measures.
Microsoft offers several recovery options once a computer hits the skids: