My Audi suddenly cut out when starting and electric windows would not work. RAC attended and after a hour they had fault codes, mainly the cluster dash board faulty. After they left, about a hour later, I disconnected the battery and tried again, no good. A hour later I took the battery out my key, cleaned it. Put it back in. Then pressed the key near the ignition, I could not believe it, all started, no problems, Wow.