It will not send an email. If you download, it is faster and more reliable. Why would you need an email? If you have the key file on your desktop, follow these steps:
Close DVDFab and remove any discs from optical drives. If you do not have the latest version installed, download and install it, then reboot your PC.
Right click on the key file, and from the context menu select "Open" or "Open with...". Windows will ask you what to use to open the file if it does not suggest DVDFab.
Click the Browse button and use the box that opens to navigate to C:\Program Files (or Program Files (x86)\DVDFab 8\ and select dvdfab.exe to open the file.
DVDFab should present a message that it was registered successfully and then open. Use "?"->About to view the welcome screen and make sure all your purchased options show your name, "Enabled", and "Never Expire".