Okay, for the SERIAL #, go to your Outlook. Iphone 6 Under 100 Unlocked. com or Hotmail account, DOUBLE-CHECK YOUR JUNK/SPAM FOLDER! I have seen license keys go there before - that's where my last license key went. They may have 14-day junk retention limit. Even so, if you re-login, and you have legally purchased, they can 're-send' you the same key, if your junk mail expired. Unlocking Cricket Samsung Galaxy Phones on this page.
THEN, here is the. You didn't say WHERE you purchased from - If it is Microsoft or a valid re-seller, you should always have access to re-download your key/license.The above link gives good info regarding logging into your 'myaccount' area, in order to review or download items you have purchased. As for how to install it, just double-click the downloaded file; if I recall, it is a self-extracting file that will run its own 'setup.exe' once you download and double-click on your downloaded file (just save it to your desktop, that way it's easy to double-click on it). I believe you will be allowed X number of days to use it, 30 or 60?; and then you must enter your license key that the vendor emailed you in order to fully/legally activate it.
You also did not say what version of the operating system you are running; sometimes, having that version information is helpful. You can go to a Windows command shell and verify; click Start, type 'cmd' and press Enter. Are All Nexus 5 Phones Unlocked. Then, at the command shell, type: ver and then press Enter. That will return something like: 'Microsoft Windows [Version 6.1.7600]' (that mine, which is Windows 7 Home Premium 64-bit). I hope I was helpful. Please remember to Mark as Answer, if I have helped you resolve your issue.