Tried to uninstall and reinstall the driver. Did not work.
Tried to use System Restore. Did not work.
After Googling for it, this is what works for me:
1. Shutdown the computer.
2. Unplug the power socket.
3. Remove the battery (if you are using notebook)
4. Wait for about a minute.
5. Plug back everything and it should work just fine after that.