Doing a hard reboot during a Windows Update is asking for trouble, but it is very possible you can simply restore your computer to a point before the last Windows Update. Windows is smart enough to automatically create a System Restore Checkpoint before installing updates.
Follow the instructions here
> Method One, steps 1 through 5 > scroll down to Method Two, step 6 > System Restore
Note: parts of that tutorial are actually links to other tutorials to help keep the clutter down. If you get confused and can't follow any of it, just say so, and I'll give you the instructions myself.
Once inside System Restore, you will want to restore to the last checkpoint that was created. It should be named something descriptive like "Before Windows Update". Follow the prompts, it will ask you to reboot at some point.
If that doesn't fix it, tell me exactly what you did, what you see on the screen, and I will do my best to assist.