Just a brief reply from me - I am sure a more technical one will follow tho My guess is that ImgBurn is waiting for your drive to do something, you said yourself the drive is happily spinning away.
Can you copy/paste the log from IB before you re-boot ? That might help, also is the firmware upto date for your drive ?
Finally, as a last resort can you not open the drive with the manual paper clip overide ?? There should be a small hole on the front of your drive, when stuck if you carefully unfold a paperclip and poke it in there the drive should reset