Hello Lars,
you should have a look at Adobe's database, to see what's stored/saved about your accounts. Here you will find general infos about your Adobe Account
https://www.adobe.com/account.html and to find your serial number have a look there http://helpx.adobe.com/x-productkb/global/find-serial-number.html
If you wil find your serial number there you can also load down a trial version and change it after that into a "correct" version.
If necessary and for further questions click throughhttp://helpx.adobe.com/contact.html and if "open" please use the chat, I for may part had the best experiences. I quote from Adobe's employee Preran: The chat button is activated as soon as there is an agent available to help.
Hans-Günter