Cerb40 not recognized by windows except in boot

Out of sudden when I debug my program on Cerb40, the Visual studio frozen.
I try to redebug, but I got Hardware not found in VS.
I unplug USB cable and plug it again, but no luck.
I try to run the device in boot mode and Windows recognize the device as STM32 BOOTLOADER.
Of course FEZ Config can not find the device.
What now? Did someone else experience the same thing?
Any information what that means would help me.

Erase your app with mfdeploy?
reflash with dfu and mfdeploy?