System Restore is built into Windows, and it is a way to undo system changes without altering personal files. You may need to undo the changes that were made during the aborted update. Once you are able to log on, you can repair the problem. Before doing any of the following, see if your computer will reboot in Safe Mode. This process will bypass the normal booting sequence of a computer. Switching on a computer system can be done from a number of modes, one of which is Safe Mode.
However, if it gets stuck, there are things you can do to fix or work around this issue. If it works, you can then run the necessary updates manually. Don't panic! This process shouldn't take too long, and you should be able to log in normally.
