its quite common with the preinstalled sim. get a fresh one at vzw and you wont have a problemIn your DNA box, there is a metal tab that has HTC on it. It also has a little "tooth pick" hanging off of it. It will open the little tray right of the power button. That's the tool the store used to mess with mine. I also have been getting the no SIM card logo, just haven't done anything about it yet...
I'm having the same issue but still cant figure out what common trends trigger it. I've taken it to verizon and they have replaced the SIM card and it was good for about two days. This error has been happening at random intervals and like the rest don't know it has happened until i notice my phone has been quiet for too long and realize no signal!
I toggle into Airplane mode and back to give it a quick fix, but sometimes it seems to get hung up on turning off the radio. Perhaps that's a clue to the root cause of error, but that's just speculation.