I just upgraded my laptop from Windows 7 to Windows 10 and found that I am unable to start Virtualbox VMs configured with a bridged adapter.
See the configuration below:
WINDOWS FIX: Ive' Fixed it by downloading a new VMbox installer from the Official Website Here.
Dont worry about your VM's they will not disappear if you override your current installation.
NOTE: If you already have the latest version, you need to export all your VM's, unninstall your current VMBox and install it from new installer.