my key fob has stopped working and when I open my door with the key the alarm goes off can anyone help please

Stupid question but have you tried replacing the battery.

yes its not that it just stopped working the other day

I suggest retraining your car to the remote...

Insert the ignition key and turn from position II (Ignition) to position 0 (All off) and back four times within three seconds.
Remove the ignition key. The locking control system is now in "learn mode" for the next 20 seconds and the red warning system LED (By the clock) stays on continuously to indicate this.
During the 20 seconds press one of the transmitter buttons. The remotes signal and code number is learned by the locking module and is indicated by flashing the warning system LED.
Wait until learn mode times out (20 seconds) or switch the ignition back to ON.

I have just tried that but it wont work the red light won"t stay on it just flashes

I can only see one red light between the temp and petrol gauge and it just flashes

Thats the immobiliser, that light should also flash. If its not happening, you may not be turning the key quick enough...?

I struggled when I last tried this to be honest...

[sup]there is no other light that will come on I have tried again since you said[/sup]

That way of retraining the car won't work on a 2008 Focus, I don't believe. That was the old style way of adding keys, now I believe you have to take them back to Ford to have them reprogrammed on to the car's GEM module.

See its difficult to tell if the key is doing anything really. Can you 100% confirm the battery is a ok and that it is making contact with the terminals, its not installed the wrong way round etc.

Have you dropped the key recently?

There is a key cutting company called thompsons that do them.
Just for a normal 3 button key not the flip as he didnt do them was going to cost me £95 all programmed in.
Not sure how much ford would charge for that.

i had a problem with my fob in the end after much messing about i soaked the circuit board in wd40 next day working a treat!

Ford quoted me £145 for a standard remote key or £165 for a flip key, got an auto locksmith out next day, £130 all in for a flip key...