Car wont start.

[trophy427]

My battery went flat the other week so I removed it and stuck it on charge.
I fitted the battery this morning but still wont start there is plenty of juice in the battery.
The immobiliser light is on and only lets the engine crank for 2 seconds. Im sure the immobiliser needs resetting does any one no how to do this I have left the key in the igntion to try and re sync it

 

[trophy427]

Dont worry after a lot of swearing and threats of sending the trophy scrap yard the immobiliser went off and she now starts. lets go for a drive now