Welcome to the forum.
What, exactly, is the problem that you are having?
If you are getting error messages, or dialog screens, please share those, in exact detail.
Where did you purchase your copy of PrE 12?
Was it part of a PsE & PrE bundle?
Did you buy the download version(s), or physical media?
Did you have any issues with installation?
Do you have an active Internet connection?
Good luck, and please let us know a bit more.
Select a reason, then click I STILL NEED HELP to activate Premiere Elements chat for help from Adobe
Please elaborate more on the steps and the issues(or errors) you are getting while registering..