Unable to run after downloading Cura 4.3!!!

[MorgiedM79 0]

Was running Cura 3.6. Downloaded the Cura 4.3 update. During the install of 4.3 an option to uninstall the old 3.6 version popped up. I chose yes, but was given the "unable to uninstall Cura 3.6. Would you like to install 4.3 anyway?" I chose Yes

 

Cura 4.3 installation completes. I am prompted to "Launch Now" at the end of the installation. I choose "Yes" and I am faced with this error message:

 

I run as Admin (even though I am an admin) and the same message. I have engineers needing to run this program on a company computer. I figure I will just run the old 3.6 version.:

 

 

I choose Ultimaker Cura 3.6.0 (has been running perfectly since March until now) I now cannot open the OLD version and get the same error:

I have been searching through forums for 2+ hours and have tried everything. The compatibility mode solution, the uninstaller does not work from either program file or the control panel, I have check the Security Tab under properties and I have full control. Please help!!