For those that are getting an error message about no registry data found (I had the error too), are you running 64-bit Windows? If you are, your Digital Product ID is in a different key. You will find your DPID in "HKLM\SOFTWARE\Wow6432Node\Microsoft\Microsoft Games\Halo". To get your Key via the CD Key Recoverer, you will have to right click the DigitalProductID in the key and modify. Highlight all the contents and right click -> copy. Next, navigate to "HKLM\SOFTWARE\Microsoft\" Right click the "Microsoft" folder (key) and Select New -> Key. Name the new folder (key) "Microsoft Games" without the quotes. Right click THAT key and create new key. Name that "Halo" without the quotes. Next, in the field on the right with the newly created Halo key opened, right click -> New -> Binary Value. Name that new item "DigitalProductID". Finally, right click the binary -> modify. Right click the "value data" field and paste the contents you copied earlier. Hit ok. Your CD Key recoverer should work now if you had Halo PC installed under a 64-bit OS.
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