Alternator has nothing to do with the process of starting a car,

granted it does charge the battery but the act of jumping it from a working fully charged battery or a jump car rules the alternator out.

BUT it has to be connected up right.

NOT TO THE BATTERY!

Jump leads from assist car red+ to your red +,

black - connects to the steel/alloy of your engine,

otherwise the assist car is trying to charge your possibly bad battery,

connecting as stated will give a much better chance of starting the dead car.

There is such a thing as battery internal resistance.

Try as suggested with the jump leads,if it does start then the battery is suspect,

if it doesn't then the starting system is suspect,

battery/clamps/leads/earths and starter.

Thoug from your description it does sound like the starter is shot.

Very much sounds like battery/starter or connections .Alternator only charges the battery,engine will run without it.Try jump starting the car with the earth lead attached to the engine,rather than the neg terminal of the battery,just in case there is a fault with the main earth lead to engine.

Thanks for your replies. Ok should have thought of not connecting the neg to the battery but to the car metal itself. The symptom is that of a flat battery one would have thought, the battery has a sensor which suppose to tell you when it is good and charged/discharged/faulty and it is showing that the battery is good and charged however tomorrow I will test the battery under load. I keep thinking about the starter motor, it does attempt to turn the engine over but behaves just as if there were a flat or low charged battery, normally I would disregard the starter motor because of this, they tend to work or not or make somesuch noise that it is easy definable. Am I wrong to assume this, I have never known this fault to occur because of a bad starter motor

Ok, I checked the voltage under load and it drops down to 7 volts, can the soleniod/starter motor cause this? because the battery checks out ok

One tip when jump starting frog cars l put the leads on and then let it equalize for 20 minuets don't run the engine on the other car it cause surging and after all its French electrics !