Audi ont turn off or start - 1990 Audi 100

Don't start ? How don't it start ? Turning the key nothing happens or the engine spins but doesn't start an run ?

You destroyed your engine. It will not start. What is turning most likely is the starter

I assume not cranking? Or cranking, but not starting?
No other work done while battery disconnected?

Sounds like your security system thinks your stealing it. Try locking and unlocking manually. Jump starting can sometimes damage electronics not usually a good idea. It is better to disconnect the battery and charge it then reconnect it. You may have blown the EBS fuse which may be mounted ont the ebs computer.

you may of dislodge a main fuse, check them for security and integrity

its 4 saftey needs to b there but u can leave a window cracked

replace the coil pack, sounds like it is over heating.

Starter switch. Plastic and cheap, my 98 A6 did the same thing... I replaced thousands in parts, turned out to be a cracked ignition switch which is a very common Audi problem!

Replace the starter. The starter drive which is called a Bendix on the end of the starter is broken.