Which AMD processor do you have?
Have you manually gone to Windows Update and ensured you have all of the Windows and Microsoft Updates, including those that don't install automatically?
Have you got the latest version of Quicktime?
When did you last run Disk Cleanup and Disk Defragmenter?
This is my processor: AMD Athlon II X2 240e
I also loaded the latest version of Quicktime today (forgot to put that in my "what I already tried")
I just ran the Windows Update and one failed with this error: Code 800B0100 Windows Update Encountered an Unknown Error. When I click Get Help with This Error, nothing runs.
Running Disk Clean up and Defrag now.
That worked to update Windows. I am using Norton AntiVirus and I had to disable it during the install. I also disabled it while trying to open PE 12 to no avail. Defrag and disk clean up are done and PE12 still won't open a project.
It's hard to say what's going on with your machine. Premiere Elements should run like a top on your system!
Perhaps another user has some suggestion.