Am I correct in thinking that a car battery can suddenly totally discharge and die ? Two hours after using the car ,with no problems, there is no battery power whatsoever. I've put it on a charge but expect it will need a new battery.
Battery is about 7/8 yrs old.

JBL

 

Certainly can! Some years ago I drove into a filling station in a Golf GTI (Mk2 - the best) and when I tried to start the car it was completely dead - not even a dashboard light! Got home after a jumpstart from the RAC but the car was only kept going on the alternator.

The battery on my MY03 WRX died after 2 years 8 months - it was replaced under warranty BUT it didn't half b****r up the alarm which thought someone was trying to steal the car and made an awful row in the underground carpark!