I had an E6400 Dell with an issue where his Verizon air card (PC770) would not connect up every time. It would say device unknown. I looked at device manager, and it showed the NEC driver as have an error code of “Code 12: This device cannot find enough free resources that it can use”. After some goggling, and failed attempts, I found a fix!
I ran this command in the command prompt (right click->administrator in accessories) :
bcdedit /set CONFIGACCESSPOLICY DISALLOWMMCONFIG
rebooted, and he has not had an issue since.