1) Squeeze the 'SAAB' Griffin emblem on the back of the key, and pull the 'key-ring' portion of the key out, a metal emergency key blade will slide out.
2) Gently pry the two halves of the remote apart from the exposed concave end of the key you just exposed with the tips of your thumbs, it will come apart in two pieces. If you can't pull it apart with your fingers you can put a flat-bladed screwdriver into the little rectangular recess between the two halves and twist.
3a) Pop out the old battery from the plastic back cover, and pop a new one in it's place - make sure the little button on the battery faces the circuit board in the front half of the key.
I think the battery you need is a CR1632.
3b) Sometimes the little metal contact tabs that touch the side of the battery get bent too far out of the way, if yours are folded over away from the battery, gently push them back to pointing upwards.
4) The thing then just snaps back together, as long as the battery was just dead it won't need re-programmed, just put it in and out of the ignition a few times.
As far as re-programming goes you have to have a Tech2 (SAAB factory diagnostic tool) and a current subsctription to the SAAB service network to give the Tech2 a security permission to access the anti-theft system of the car - usually only a well-equipped independent or dealership will have this.
so there is no need to reprogram? I had an a4 and i used to have to do some combination of lock unlock button pushing with the key on aux to get it to work after putting a new battery in. Anyway thanks