Rebooting either before or after the network connection drops fixes the connection but if the troubleshooting wizard was run, the reboot results in a BSOD with DRIVER_POWER_STATE_FAILURE error.
I downloaded the latest Broadcom drivers but Windows insists that the default driver is current and won't allow installation of the vendor driver (which is an earlier version number, but has a more recent date than default WIndows driver).
I've uploaded the latest two minidumps and a full dump to Skydrive. (http://sdrv.ms/17WIvSD)
Any help would be appreciated.