Without another working backup SD card, Your options are pretty limited other than powering it off then removing SD card and making sure the SD card contacts are clean and the card is correctly installed.
I do not think you can get the final updates for free on the DS708 like a few people mentioned they did. I tried to do it with a new SD card from my DS708 software suite and it only installs the new version OS system (no car make updates be available) I would not put that card with the new OS firmware into the DS708 for fear you I may no longer be able to use the old software backup cards I created or something in it will cause the scanner to just time out and quit later.