I was following Sam Morris' method but found not luck. However, the way he found his solution inspired me and helped me to find my solution on my ThinkPad T400 bought back in 2009.
The quick answer is: change the value of the registry entry, HKCU\Software\Lenovo\Factory Recovery\done, to 0. For my case, the Q:\ drive was never altered to turn on the forbidding flag. It was totally done through this switch in your system's registry.
For people with patience on reading how I found out, this is how. I also use Process Monitor to track what recovburncd.exe did after launching (up to the point where there was only the "Cancel" button for me to terminate it). So I tried to identify (within the activity list in Process Monitor) which activity prevented recovburncd.exe from enabling the "OK" button. Then, I saw the registry entry mentioned above had value 1, reminding me of the similar terminologies in the other two ways (Sam Morris' method and the service_done.ini method) of fixing the "done" flag. It was a bingo!