Look, only a part of the key is shown on the about dialog.
Are you receiving any other error after pasting the new key? If not, why don’t you stay with it? When does avast updates expires with this new key?
The key is on the Windows Registry and not in the files under avast folder.
The protection is against piracy of the Pro version or ‘renewing’ the trial period. The Home version shouldn’t be affected at all.
There were some problems - in the past and nowadays, with registration - if you uninstall and install the new jollyroger file, it shouldn’t be a problem… but seems that we’re wrong…