My PC is on this screen saying "Installing Update 243 of 243"

[Chaza_]

It's saying Installing Update 243 of 243 and is stuck on it not doing anything.

 

[basroil]

Let it go for a few hours. If a day or more has passed, then reboot and hope it recovers. If it recovers, try to install the updates again, but only about 20 of them at a time!