Changing SIM Cards?

My Sony Ericsson w300i originally had a 02 SIM card. Now I want to use Orange but when I put the Orange SIM card in it says %26quot;Insert Correct SIM Card%26quot;. How can I solve this?Changing SIM Cards?
I'm not familiar with them but it sounds like Orange is a cell phone company? If they are then that would normally mean your phone is locked to your previous carrier and doesn't recognize the sim card you've put in the phone. You would need to get your phone unlocked. One of the easiest ways to get an unlock code is to look on Ebay.Changing SIM Cards?
you need to contact your provider so they can give you the unlock code for your phone.Changing SIM Cards?
Your phone is locked to the O2 network. You need to get it unlocked to accept all other networks. Any phone accessories shop on the high street or stall at your local market will unlock it for you for about a fiver or tenner. Or you can buy the unlock code off ebay.