Hi,
I'm sorry to bother though I'm a newbie and I can't really figure out what to do. And I really hope you could help me

So I've used AppCleaner to clean my mac from unnecessary stuff. However it turned out that some Microsoft Office files were deleted and placed in the trash bin. The thing is that when I enter my Word I get a notification saying: "Welcome to Microsoft Office 2011 …" and I have to provide the product key which I don't have because Microsoft Office was given to me by mu University when I bought my computer. I was thinking that by simply placing all the deleted files from the trash on the desktop would help but it didn't. Does anyone of you know how could I bring back the files (they're in the trash bin now) to their original location and if that's going to solve the problem? I've checked that "put back" and "command + delete" in the trash bin does not work.
Sorry once again,
T.