Nexus 7 issues with lagging, boot-loops, NFC greyed out, and depressed CPU states
Please erase all data and the dalvik-cache (if you have recovery).

Are you using the stock or custom ROM?

This looks to me like a bug in the ROM to do with NFC - this is the only reason the device would lock up like that.

If you are using a custom ROM, I suggest you contact the ROM developer with the logs, if not, check for a software update.

EDIT:

The NFC service will only run if NFC is enabled - if you disable it, and then reboot, it should no longer be active. If it is you can kill it via Settings-&gt;Apps-&gt;Running.