Adobe Premier Elements and Photoshop Elements 2021 won't open, Windows Version 10

If @ShelLuser's solution does not work, will the Organizer open from the Welcome Screen?  Have you ever reached a screen where you can enter your serial number?

Your best bet is to contact Adobe Support to help you with installation issues.  It's one thing they can usually handle better than users on this forum.

If you check the task manager ('advanced view') does it still list the processes?  Also: if you just start the programs using their default icons does the welcome screen show up normally?  So: can you start the software stand alone?

If this continues to happen then may be you can try the option explained here:

https://community.adobe.com/t5/photoshop-elements/launch-of-pse-2021-freezes-at-initialization/m-p/11657092

This is a very weird issue, one which is still bothering me as well from time to time. At one point I was convinced that the DNS settings could be related to this problem, only to run inthe the exact same issue one week later.