Licence key doesn't work

[wolfmagic]

I purchased ExamDiff Pro about six months ago. I had to take my PC back to factory settings a few months ago and then tried to activate the program after downloading it again using the same licence key. I got the message Error Decrypting File so it didn't work. I had some correspondence with PrestoSoft on how to fix this but they didn't help - they just said keep using the same licence key, which never worked again. I think the program is great and want to keep using it so, even though I already had a valid licence with about six months left on it, I just bought the program again, got a new licence key (for version 9) but got the same error message Error Decrypting File when I tried to activate it. I think the problem probably lies with my PC but I don't know what it is or how to fix it. So now I have 18 months worth of licence for an excellent program but can't activate it. Does anyone know of a possible solution? I use Windows 10.

[psguru]

Please contact us at http://www.prestosoft.com/ps_email.asp, and we'll resolve your issue.