sprked

I registered FSUPIC 3 on FS9 about a year ago, paid for it and got my key and it worked fine. I recently changed to FSX and deleted FS9 and after a year I have gotten sick of the awful wind alterations at high altitude in FSX which doesn't have FSUIPC which I found helped a lot in FS9. I downloaded FSUIPC 4 and went through the installation process until I got to the point where you enter your registration. I presumed because I bought it the year before I would press 'check existing registrations' it said 'tje registration was cancelled or doesn't check correctly' so I ran the installer again and pressed enter new registration, entered my details exactly as they are in the email I received last year but no, still it doesn't work; comes up saying 'sorry, this key is not valid for FSUIPC registration.' At this point I was very tired with the many many many many problems I have had so far with flight sim... My key is valid because I bought it. Im not buying it again... Why is it saying this and how do I make my key register FSUPIC 4 on FSX please please help me! Thanks, Michael