am experiencing the most freaking problem on my n900 when i turn off the device then turn it back on there is no signal and instead of the signal bars there is a sim card icon and i cant use the gsm so i have to turn it of everytime and remove my sim card and then insert it back again then turn on the device in order to make it work whats the problem is it hardware is it software have anyone experienced this problem its a big blow for me & making me paranoid

I Experienced that but, it was a bad contact in the SIM. If you checked that already, maybe it is a different issue.

(DaKing: For future reference, please use punctuation... This was quite hard to read.)

ok i will do that the second time
but i dont understand what do you mean by bad contact in the sim?

Hi DaKing. Here are some punctuation symbols for future posts. Just cut and paste where you need to and I'll post more if you run out.

.................. ,,,,,,,,,,,,,,,,,,, ;;;;;;;;;;;;;; ::::::::::::::

By bad contact, StimWin meant where the simcard inside the phone contacts the pins in the n900. What you may want to do is take the sim out, and clean the metal pads on the surface. Not with water, but an alcohol based cleaner.

That is the way you are supposed to do it, personally, just the act of taking it out, wiping the contacts with your finger and putting it back in is enough to make it work usually...

ok i will try that, but today i turned off the device then on. and everything was normal but after 2 hours of using the phone without rebooting the bars went of and the no sim card came again for 5 min.
then it worked again alone so should i worry or might it be only software.
i dont think it is contact because today it worked wothout taking the sim out :S

That definitively sounds like a bad SIM-card. Or bad connectors where the card goes. If you've used your SIM-card for a year or more, I guess you should clean it or replace it.

I think bad contact is the reason .
There can be some dirt causing the time-to-time malfunction
(ewen little stroke can make move inside phone ,and stop this connection)

Suggestion : I'm ussing a normal rubber for this purpose ,It's not agressive and not liquid.

If this will not help, you should try another working SIM.
Depending on the result - please your operator to change your SIM or visit Nokia service.

yea my sim card is like 4 years old, but clean but i will replace it in case since this problem is new.
Rubber ? mm i rub the n900 with a pencil rubber or i rub the sim card and are u sure its good?
thanks alot all i hope i can fix it

its getting more and more frequently