Hi,
I have a Windows 8.1 system which runs Photoshop Elements 12 OK so it does work, we just need to find out why it is failing on your system.
Your user is an administrator isn't it?
Try the following.
Load the Welcome screen
Hold down the Ctrl, Shift and Alt keys and then click on the Editor button. Keep the three keys held down until a message box pops up asking if you want to detelet the settings.
Click on Yes.
Are you familiar with computers, if I asked you to look at the windows event viewer, would you know how to. (sorry to ask that question but it affects how much detail I have to give).
Brian