Please clarify your question.
Are you working with Photoshop Elements 12 and Premiere Elements 12 or just one or the other? What program can you not open?
And, is it just the Premiere Elements Editor or Photoshop Elements Editor (not the Elements Organizer 12) that you cannot open?
What computer operating system is your program(s) running on?
More details, please. The following are two blog posts details may help us as you offer details of your specific situation.
If this is a Photoshop Elements (photo editor) question, then the question is best answered in the Adobe Photoshop Elements Forum
We will be watching for your follow up in order to advise you accordingly.