This is not Adobe. Rather user to user.
We will try to help you but typically Adobe is the only one who can resolve serial number issues.
But, whether here or at Adobe Chat, details are needed.
1. What version of Premiere Elements is involved and on what computer operating system are you trying to run it on?
2. Did you successfully install the version and ran into problems only when you went to use Help Menu/Update or some
other scenario? If so, what was the exact message that you got from Help Menu/Update? What were you seeking to update -
Camera Raw or an Update for the version that you have?
We will be watching for your details.
Add On...If you have the current version and want to contact Adobe Chat, please click on the following link
which is set to
Adobe ID, Signing In
Adobe ID. Sign In, and Account Help
If the link does not hold its set, then you will have to navigate to the Chat Panel using the above titles as guides.
At this moment, the Chat Panel seems to be in working condition.