First, install and run on your PC the utility provided by Microsoft. It is developed to find and solve common problems with hardware and devices. If doesn't help, go to Start > Control Panel > Hardware and Sound > Bluetooth Devices. Select your device, click Remove and then Add. Check the My device is set up and ready to be found box, click Next and follow the instructions. Also, from Bluetooth Devices click the Options tab and check the Allow Bluetooth devices to connect to this computer box. Click OK and restart the PC. For further solutions check the Microsoft Support page.