Purchased a 32GB 3G Nexus 7 from Google.  First one had a cluster of dead pixels so I returned it along with the Micro-SIM it came with.

They sent me a replacement, but it did not come with a Micro-SIM.  So, I had some back and forth emails with Google for about a week, trying to get them to send me a Micro-SIM.  I ended up just going to an AT&T corporate store to get one.

That was yesterday.  I've had this Micro-SIM in the N7 now for a day and I did pay $15 to activate one month / 250MB of data just to try it out.

It works, but I keep getting two different messages on the screen randomly at different times, that say:

SIM card removed
The mobile network will be unavailable until you restart with a valid SIM card inserted.

I press the restart button and once it's on again and on the pin screen (where I enter my 4-digit code), it says, "NO SIM CARD" beneath the number pad.


I'll proceed and enter my pin.  Do some stuff, play games, check email, just use it regularly and all of a sudden I'll get that SIM card removed message again asking to restart the N7.

The other message I get as well (also randomly) is:

SIM card added
Restart your device to access the mobile network.

Anyone know what's 'causing all of this?  Any fixes?