I thought you might be interested in looking at Change CD key without re-installing?.
https://forums.bohemia.net/forums/topic/106900-change-cd-key-without-re-installing/?do=findComment&comment=1779224
× Pasted as rich text. Restore formatting
Only 75 emoji are allowed.
× Your link has been automatically embedded. Display as a link instead
× Your previous content has been restored. Clear editor
× You cannot paste images directly. Upload or insert images from URL.