Alfa Romeo Repair: GTV Recurrent electrical failure, neg terminal, electrical failure

Question
Would a faulty doorswitch cause my whole car to lose power? I was suspecting a faulty earth as I suspect that the door locks operating would be in response to my alarm system arming because of the loss of power?
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Followup To

Question -
Stephen, I have a 1997 GTV which starts fine, however it sometimes loses all electrical power while driving. The ingition light and ABS light come on and when this happens the alarm/immobiliser arms itself. which means I have to press the fob button to disable the alarm and then re-start the car. It doesn't always start immediately but I have never had to wait more than a minute. Sometimes while I am driving the central locking activates then de-activates the doors.

Any help will be gratefully received.

Answer -
I do not have access to data for newer vehicles as I am in the usa. However, I would suspect that the drivers door switch for the security system is faulty or loose. It should be tested.

Answer
Yes, the grounds could be the problem. Start with cleaning both battery terminals then take apart and clean every ground connection that you can find. If you have a DMM (digital multi meter) then you can measure the voltage drop at the grounds by putting the neg connection at the neg. terminal of the battery and going to each ground with the positive connection and you should have less than 0.3 volts. Or, use the ohm meter with the same connections and you want less than 0.5 ohms.

I misintrepreted what you meant by losing power.