I have a Huawei Ideos x3 which up until Friday I was using with my Vodafone sim card with no issues, now it appears to not be registering with the phone.

The problem being above signal bar there is a little 'x' showing and what looks like a sim card picture with an exclamation mark in it. I have tried to manually search for a network (Vodafone 2G & 3G as well as 2Degress show up) but am unable to connect to any. I also have a 'please insert sim card' message when phone times out.

I know my sim card is still okay and working because when I put it in my old Nokia everything's fine. I have trawled google for possible solutions but ended up more confused, can anyone help?