By default, a simple mouse movement is enough to wake up your PC. To disable this boring option and prevent any accidental risks of unwanted awakening, follow the guide.
Open the start Menu then enter Mouse. You can also go through the Control Panel.
Click on the tab Equipment then double-click the device concerned. In this example, this is Mouse HID.
Then go to the tab Power Management then uncheck Allow this device to remove the computer from standby mode.
Validate by clicking on OK.
From now on, your mouse will let your PC sleep quietly. Note that you can do the same for your keyboard by taking the steps below.