Hi i just answered a call on my n900 and after i ended the call, my n900 stopped recognizing the sim card. I rebooted, checked to see if it was in gsm mode, nothing worked. I have put my sim card in an other phone and its working fine. So, the problem is with my N900. I am running PR1.3 and i have overclocked it. Its been running fine since many a month now and i have not installed any apps in a while too. It was not overclocked when i last answered a call, it was at the default 600MHz clock. There is strike mark against the tower logo shown where it displays the signal strength in the top menu. All the applications are working fine though. Kindly help me. Thanks.