How to Fix Windows Update When It Gets Stuck or Frozen

Here's how to fix Windows Update when it gets stuck or frozen. Try running the Windows Update Troubleshooter, which you can search for in the Start menu. If that doesn't help, you can try deleting Windows Update's cache by booting into Safe Mode, stopping the wuauserv service, and deleting the files in C:\Windows\Software\Distribution.

Source: www.howtogeek.com