2008 Carrera S with 81k miles all of sudden would not start, between errands. Previous days when starting, hot or cold, sounded like weak battery or cable issue, slow to turn over. On the day of death, car was hot and clicked like battery dead but all electronics reset and began running again, engine did not. Turned out to be a short in the starter, cause electronics to reset. Weird.

 

I had a loose cable, fixed under CPO.

 

I had a similar issue with mine (and I think it's a common issue in 997.1 cars), so I had the alternator and infamous cable replaced. So far so good.