C220 (2008) - car won't start! please help

Hi all,

I stupidly left my lights (2 days) on and came back to find that the car doesn't start! I have very little knowledge about cars...

I tried jumpstarting the car but the key doesn't turn - When the battery is connected to the jumpleads the lights/radio etc work but the car won't start. Once the terminals are disconnected nothing works!

Do you think I need a new battery? I spent ages trying to look for something similiar on here but no luck. Also somebody mentioned that codes may need resetting? Is this correct?

I am also getting the following messages on the dash but have no idea what they mean:

1. ABS and ESP currently unaviable, see manual.
2. Restraint sys malfunction consult workshop.

Any help or advise would be greatly appreciated.

Thanks

(PS I may have originally posted this in the wrong section - sorry!)