If you bought from Adobe, or Registered with Adobe, you should be able to log into Adobe.com with your Adobe ID, and then navigate to My Products (think that is the correct name), where your Registered Adobe programs, and their S/N's will be stored.
If they are not, then a call to Adobe Customer Support (not Technical Support), should be able to locate that S/N for you. I would have a copy of my invoice handy, just in case.
Thanks for a quick reply.I´ve bought the programs from a reseller and registered the serial number for Photoshop Elements 11 but not Premiere Elements 11. Both programs are bundled on the same CD/DVD. Do you think the S/N för Premiere could be traced with the S/N from Photoshop? I think the receipt went the same way as the envelope
I do not think there is any way for anyone here to help you (we are just other users) so you are going to have to contact Adobe
Forum for Download & Install & Setup problems
And tell your wife to be more careful about throwing things away