I have a Nokia 3650 (S60 1.0) and a Panasonic X700 (S60 2.0) which both intermitterly say "Insert SIM Card" or "SIM card rejected" on bootup. I managed to format my X700 and it's working OK so far, but my 3650 is an absolute shocker. The *#7370# code doesn't work properly and the local service centre in Newcastle (Australia) are a bunch of bludgers and claim that there is nothing wrong with the phone. Both phones are unlocked.
Fortunately, the X700 is still under warranty, so that's ok for me, but not the 3650. I also backed it up using PC Suite too but I don't have a backup for my 3650.
Can anything I've done/installed would cause this? I had Mobiluck, Smartmovie, Psiloc System Tools (Not on my X700, it got nuked when I previously formatted and restored my backup ages ago).