Battery dead after 6 months of storage

My son has 2004 911. Car has been garaged 6 months. Battery recharged. Starter wont turn over. Using jump leads from another car the starter appears to want to turn, but head lights left and right flash alternatively instead. There is no large draw when jump leads are attached. Any ideas on what could be causing this. Car was running fine before garaging.

__________________
This post was auto-generated based upon a question asked on our tech article page here: Pelican Technical Article: 911 Carrera Engine Starting Troubleshooting

[Wayne 962]

The battery in your car will drain a little bit every day if you don't put a battery maintainer on it. After sitting drained / empty for several months, the battery is probably completely dead and will probably not come back to life again. I would replace the battery, particularly if it's the original one in the car. I have an article on this right here, as well as the steps required to install a battery maintainer: http://www.pelicanparts.com/techarticles/Boxster_Tech/81-ELEC-Battery/81-ELEC-Battery.htm

- Wayne

[Wheel Dynamics]

He's right, for around $60 you can save the life of your next battery.
Pelican Parts - Product Information: DEL-021-0128

[FPB111]

Are you hooking the jumper leads to the battery or the posts in the engine bay? Either way your battery sounds like it is too far gone to bring it back.