When you purchased the new seat license, you should have been given a new serial number. After uninstalling EViews and during reinstallation process, if you used the new serial number everything should be fine.
In any case, to save you the hassle of uninstalling and reinstalling again, in the directory where EViews is installed, you will find a file called lisource.txt. Rename that file to something other than lisource.txt and then start EViews. EViews will either start with the new serial seat license number or indicate 'No licensing information could be found for this copy of EViews'. If no licensing information found, select 'Install a standalone license ...' and press OK. From here enter the new serial number and press 'Register now'.