I updated my computer and my qb doesn't want to open now

Desktop or Online?

For Desktop, try holding the Control key (CTRL) and double clicking the QB icon and HOLD the CTRL key until QB opens.  (May take a couple of seconds.)  You should see the No Company Open screen where you'll either see your Company file or you can go search for it.  See if that works.

For Online, go download the Desktop App and reinstall it.  Then log back in and see if that works.

If neither work, give us a little more info on your computer (Windows or Mac), what updates, etc.