Car just cutted out under my feet

I Have a problem with my Opel Astra 2002 1.6V CS. The car suddenly didn't want to start, so I jump started it. Then afterwards, I was driving it at a speed of 120km/h in 3rd gear, ref counter about 5500rpm, when suddenly the car just cutted out under my feet, the head lights went dead, all lights on the dashboard went dead, not even the hazards is comming on. The spedometre gage, refcounter metre gage, en even the fuel gage didn't come back to normal (0), when the car cutted out. I Have taken out the batery, after that, it was measering 9volts, replaced it, but the car is just dead. I Have also checked for fuses that might have blown, but cannot see anything.

a Mechanic friend of mine thinks that the computer box need to be reset (maybe because of the altenator that has been overcharge or something), is this right, and how can it be done at home