I bought a 2006 Audi A3 last night. Today on my way home from work, I was messing around with the driver display settings, trying to change the clock (I know, I know, I shouldn't do that while driving). All of a sudden the screen went blank, the air bag, power steering, brake light, and other lights came on, the speedometer stuck at 70, and the turn signals stopped working.

I got home, shut the car off, and turned it back on, hoping that would reset the thing (also disconnected/reconnected the battery cable). The speedometer is still suck at 70, even when shut off. The car starts for a second, then shuts off right away. I can't roll up my window. The display comes up, but when I try to set it to English, nothing happens.

What can I do to fix this?

Thanks!