Has anyone changed the batteries on their Keys?

Decided to change the battery on my key 1, simple job..however the keyfob wont open/close the car but if i open the car with key 2 and put that back in the house so it isnt around, then sit in the car with key 1 the car will drive but it wont change to my profile?? I used a duracell battery that has a coating on it to stop kids swallowing them, i read up on this and apparently they are hit and miss with the fob. I decided to put the old battery in (even though it was hit and miss) but its still not working.

I'm wondering is there some kind of reconnection process i have to go through etc... that i havent gone through or is it a dealership question?

Thanks

J