Hi Aerbabe,
I think this is to do with a relatively new function on Sim Cards and Nokia Phones (Maybe others as well). When I last changed my phone I had a new Sim Card as well. The new Sim card has a list of help numbers and information numbers stored on it.
My phone always says how are you? when I switch it on, and I now have access to an extra menu called Vodafone on my Nokia phone. It has sub menus: Help, Information, Leisure, Answerphone etc. allowing direct access to services without having to store the number on the phone yourself.
Does your mobile have this menu? If it does go into PHONE SETTINGS, then scroll down to CONFIRM SIM SERVICE ACTIONS and select NO. This should stop it asking you if you want to confirm sim actions all the time. Your phone should just say How are you, and log onto the network.
Don't know why your phone is freezing tho. Might be time for a new sim. Does this happen when the phone is already switched on, if so, try cleaning the metal bits on the sim card and the phone with a pencil erasor! (gently) Yes...........A pencil erasor.
Hope this helps.
fwyg.