Mouse and keyboard not working on lock screen login
Make sure that your computer's Unified Virtual Hid is working properly.
1) Open Device Manager (e.g. via start menu > search device manager)
2) Click “View > Device by connection”
3) Verify that “Unified Virtual HID” is in the list
4) Right-click it and select “Properties”
5) Verify that the device status is “This device is working properly”