The most likely thing the file is, is an CD Image file, so you can either emulate it with a virtual drive like Daemon Tools or Alcohol 120% or i think Nero will open it and burn it to a CD (Not a DVD). I think the other thing it can be is not a windows used file, thats a Uni-code type format thats used in Linux to maintain a document in case and charictor format. Not to sure though, i downloaded a file a while back with the extension and it was just like an ISO file, just a CD image....