Weird Ford radio problem

[RobbieL]

I've just picked up a cheap winter focus from fleabay and the radio code doens't want to work. I've got the orignal receipt from the dealer and checked the serial number and the code "should" work.

I've completed one of those online unlocking thingies and that has given me the same code I already had - so it's definately the right code but the head unit won't accept it, it just turns itself off when I enter the code.

Anyone come across a similar problem?