September 2017
"Windows Resource Protection did not find any integrity violations."
Sorry for my incompetence
When I tried to install the updates, it said, that "We couldn't complete the updates, uninstalling updates". I am not sure what this means.
As for the new account, it had the same result, the game wont launch.
September 2017
Forgive the late reply I'm pretty busy in the moment.
After renaming the game files could not solve the problem, it is likely that the update problem (or rather deeper lying problems with Windows hinted at by the update problem) is also responsible for the problem with the ActivationUI.exe.
First make a backup of your important data if you not have already done so.
Go here and select "Update now"
This will initiate the Windows update process again.
September 2017
This is unrelated to the rest of the discussion, but with ME2 it's always a good idea to try both executables. In the installation folder under 'Binaries', you have both ME2Game.exe and MassEffect2.exe. Try launching from both.
If that doesn't work, disregard this comment and keep reading Holger's advice.
September 2017
The game is now launching, finally!
After the windows update, and reinstalling the game, it is launching normally.
I really appreciate the help. Thanks again.
September 2017
You're welcome, have fun gaming.