Do you know about that tiny little blue button at the lower left corner of the Windows 7 login screen? When an unknown person clicks that button on your computer while you are away for a quick snack or some coffee, he/she will be able to do the following to your computer:
Even though it can be reverted back easily, it might be better to disable this button on the lock screen. Please note that this trick works on all Windows versions, including Windows 10!
So let's get started by taking ownership of the Utilman.exe file located in the System32 folder.
Start by bringing up a command prompt in administrator mode, and use the following command to get permissions
takeown /f C:\Windows\System32\Utilman.exe
You should get a confirming message claiming that the executable is now owned by your user account. Great, now let's fiddle around with the executable and it's permissions. Navigate to the System32 folder and locate the Utilman executable file. Right click on it, and click on properties. You should get this window
Click on the Security tab, click on the SYSTEM user in the upper list, and then click on the Edit button.
Read and Read & Execute rights should be disabled like this
Click on Apply and you should be good to go!