: If Nitro Pro 10 is currently installed and activated, you can often find the key in the registry at: HKEY_LOCAL_MACHINE\SOFTWARE\Nitro\Pro\10\Registration (or similar path under Nitro Support Tools : Open Nitro Pro, go to the tab, and select Support Tools
: This is Nitro's official online merchant. Look for an email with the subject line: "Reference #xxxxxxx: Your Nitro Pro order" . Nitro Pro 10 Serial Number Key Finder
(the payment processor) with the subject "Your Nitro Pro order" or "Reference #". Check the Windows Registry: : If Nitro Pro 10 is currently installed
Search your email archives (Gmail, Outlook, Yahoo) for the following phrases: go to the tab