Welcome to the Community. A hardware device might be keeping your computer awake. USB flash drives and USB mice are common devices that can keep your computer awake.
To prevent a device from waking your computer. Click on start, right click on computer, click on properties, click on device manager.In the list of hardware categories, find the device that you want to prevent from waking your computer, and then double-click the device name. Click the Power Management tab and then clear the Allow this device to wake the computer check box. Click OK.