I am not a engineer so please bear with me.

I have a "T" reg Zetec 1.25 engine, and recently had a new gearbox and clutch plate replaced. Drove the car home from the garage no problem, went out later that night car started up no problem, did no more than 600 meters, turned off engine, came back and switch on, in 2nd position, the display i.e. rev counter, speedo, fuel, water, went hay wire and the trip counter went to zero, then settled down turned key to 3rd position and could not start engine, (it was like there was no power) the same thing happened again after 10 mins. Pushed car home, jumped started battery with a battery power pack, display went haywire and started.

Any ideas on this PLEASE as to why this is happening