Car won't start HELP ME
 

Hi im wondering if anyone can help me,
I have an 2002 1.6 auto A class about 9 month's ago i had a problem with the gearbox it was jumping when i selected drive or reverse. So i disconnected the battery took off the gearbox control unit just inside the gearbox sump and sent it for testing, the part failed so i started looking for a replacement from the same year same engine size ect ect. This took me around 6 month's got the part i was after fitted it put new oil in the box and reconnected the battery (which i should say i charged before i reattach it).
Now my problem is when i put the key in the ignition strange things happen it all lights up but when you go to crank the engine over nothing, all the lights go off the dashboard and when you remove tbe key they ALL STAY ON
[:s]
The Windows wont work or radio the horn will just start to make a noise but cuts out within half a second.
Now i thought maybe it was an earth problem so cleaned most them didn't make a difference, its worth saying when i try to start the car theres lots of clicking from a relay in the battery box.
Iv tryed jumping it from my friend's car just in case it was the battery it only got stranger everything works now Windows horn ect ect but when you try to start it nothing just a click from the starter motor but at the same time a click from the relay in the battery box. I have no idea now what it could be maybe because i left the battery off for 6 months? Or immobilizer ? Replaced the battery in the fob but all that achieved was setting the bloody alarm off.

Any ideas of help would be appreciated.

Sounds like your battery is bad, and can't hold enough charge to crank the starter. How old is it? Might be time for a new one.

Edit: This was solved elsewhere. It was the battery.

I have found that doing an alignment with minimum toe-in has really helped my inner tread wear.