I recently purchased a 94 Saab 9000CS that sat for about 2 years. The factory radio is in it, but the battery was dead and the original owner doesn't know the unlock code. Is there a way to reset this deck, or is there a master unlock code that I can use on it?

Most decent car audio specialists will decode the set for you. I normally charge 25+VAT for Clarion, phillips, blaupunk etc. There is no master code, but putting the code in wrong too many times can render the IC Chip corrupted so a new chip is required.

If the radio is the original Saab fitment go to your nearest Saab dealer with the registration document and your driving licence as proof of identity and they will get you the code from Saab's computer records free of charge. I've had to do this twice.