Although it wasn't funny at the time, my original Verizon Novatel USB 720 adapter was stolen by raccoons that raided our chicken coop where the home wireless setup lived. They killed all the chickens but they also took the 3G modem because it had blinking lights.
That back story might seem extraneous but it relates to this blog entry. The replacement 3G adapter was a Novatel 760. The 720 never locked up. The 760 would about once a week or once a month depending on usage.
The telltale signs were a solid light on and even powering off the unit through the VZW software would not work. I eventually just got used to unplugging it and plugging it back in after a while. It effectively would go into a coma on any computer it was used on.
Recently, there were 2 firmware updates released inside of the VZW access software. You can grab the latest software and firmware update from
here.
With the new firmware, I can no longer make the device lock up and it seems to have better receive sensitivity. Either way, I recommend anyone using this device to perform the firmware update.