I realize the inconvenience you are experiencing with your PC as Airplane Mode is greyed out. I will certainly help you with the issue.
I would like to inform you that in Windows 8.1, the Airplane mode option on the Networks area is designed to quickly turn off devices, then resume them again by turning off the Airplane mode.
If Airplane mode is enabled on your computer and you can’t turn it off because the switch is grayed out, check that there’s no physical wireless On/Off switch on the device.
If there is a physical wireless switch, and it’s set to Off, you won’t be able to turn off Airplane mode. Set the wireless switch to On and the option to turn off Airplane mode should be available.