Photoshop elements locks up. I cannot even close the organizer window. I have to reboot my computer

version numbers represent the date it was “compiled”- created.  In your case : April 2nd, 2025.
Versions are posted typically one week after that date.

Your version number 202504042.3 was, to the best of my knowledge, the last update for pse 2025.

LOG OUT OF THE EDITOR FIRST IF YOU CAN.
Uninstall pse 2025- any number of ways to do that. 

Reinstall using the link found in your product listing in your adobe account.  
 

PSE 2025 does not have a serial number- it’s tied into your computer and the email used during the purchase.