Major screw up-help?

Hi, I have been having some problems with my wife's Audi A3 (A4 Golf platform). The problem was with the temp guage reading too high but the engine temp seems fine on Vag-com and today I swapped the coolant sensor but it made no difference. I decided to see if it was a guage problem and removed the instrument cluster, I thought perhaps the needle was just in the wrong place but whenever disconnected it goes right down on to the bottom stop. So I decided there was no point opening it up or anything and just put it back in. Trouble is the car has now immobilised and won't start. I recon either it isn't recongnising the key or the cluster anymore, not sure what I did wrong but can anyone advise what I need to do to get it going again? Thanks.

Did you get all the connectors back on correctly, and did they STAY on when you put the cluster back in?

Well done. you were right, green connecor had caome almost right out by the time I took the cluster out again it's a bit of an awkward one and you are manly putting it in by touch, all OK now.
Thanks for the help
Wallace.