I don't know what Kenwood you have, but on most of them there should be a tiny little button somewhere on the faceplate, which can only be pressed with a pen tip. Check your manual if you still have it, or most manuals can be downloaded from Kenwood. However, if you pulled the power on it that also should have done it.
Sometimes a simple disconnect/reconnect of the cable at the Keg does the trick as well, or even a very slight nudge of the DMS into the Keg. If you do all that and the head unit still shows "eject," something is not right with the drive. That could be a physical defect or some system files are missing.