macadwd
Back in post numbered 3 of your thread, Arjun suggested downloading and installing the Adobe Application Manager as per the link given.
Another Adobe Staff person suggested that idea (and that link) when I was having a problem opening Premiere Elements 12, but my issue symptoms were different than yours. In my case I was getting a message that I was not connected to the Internet (which I was) and that my computer had a problem with its clock (which it did not). So, I did not feel justified in offering the Adobe Application Manager fix in your case.
But, your troubleshooting has gotten to a point where we should not exclude any avenues. Here is my blog post on my experience with the Adobe Application Manager fix. ATR Premiere Elements Troubleshooting: PE12: Sign In Failure (Connect to Internet or Fix Computer Clock)
If you have not already tried the Adobe Application Manager download and install via the link, please consider doing that and letting us know the results.
Adobe - Adobe Application Manager : For Windows : Adobe Application Manager
I would still like to see the results from a New User Account, but one way or another we need to explore all troubleshooting areas.
Thanks for all the follow ups.
ATR