Hello ms.belle,
in addition to all these hints : 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 - as already said above to find your serial number have a look there http://helpx.adobe.com/x-productkb/global/find-serial-number.html
and not to forget "My Adobe" >>> https://www.adobe.com/account/my-products-services.html
Hans-Günter