2003 Mercedes CLK 320 - Ignition Frozen

If you still have the owners manual, have a flick through it and see if there's a description on re-programming the key to the car. It could be some crazy sequence, for example : 1.with the drivers door open, put key in ignition, 2.press the boot release and unlock buttons simultaneously for 10 seconds, 3.close drivers door......... I've had a similar problem with my Peugeot after the battery had been disconnected for a while. Hope this helps, good luck.

Ok so i just downloaded a manual for your car and it would seem that synchronizing the key is a simple case of putting it into the ignition. I also noticed that the manual doesn't show a detailed list of fuses and what they're for, so perhaps you should check the other 2 fuse boxes located 1.under the bonnet, near the brake master cylinder on the left near the firewall, 2. Open the left hand door, there's a removable panel on the side of the dashboard.

Not sure that the problem is solved, but it wasn't the key(s). I simply disconnected the battery for a few minutes and let the car think about itself. Re-connected the battery, and it started right up. Go figure! Thanks for the replies, however. Cheers!