I have a Sony Ericsson K800i mobile phone. It was an 18month contract with Orange. So I got a new phone once my contract was up. My new phone is an o2 Pay as You go. However the phone itself is annoying me quite a bit and I would like to go back to using my old Sony Ericsson but it is an Orange model. I only know this because it has the wee square orange sign printed on the front of it Lol. Is there any way I can use my old phone with my o2 sim? it wont let me just now but is there something i could get done to the phone to change that? i dont want to spend money to get a new phone since i have decided to buy one after christmas (when i get some more money!) so this would be an easier option for now. if anyone knows a solution to this it would be greatly appreciated. thanks everyone!