Won't Start
 

Hi Guys.

Big PROB...
Audi S6 V Reg 2.7 BiTurbo. 129000ish Miles

Turn Ignition. Starter turn but does not start and And dash lights flicker.
Put in reverse. Still turns over. No start but also no dash lights.
Intermittent as sometimes no problem at all though problem becoming more than not.
Any ideas please as i love this car.

ThankYou

Lee