You don't actually need to create a batch file for this. You can simply make an entry in the registry.
Open the registry editor with administrative privileges and browse to the following key: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
Right-click in the right-hand panel and select New String Value
. It doesn't matter what you call this string, so just press Enter
. Now, right-click on this entry and click Modify...
and in the dialogue box type the following: C:\Windows\System32\DisplaySwitch.exe /clone
Now press Enter
and close the registry editor. When you next restart your computer, this command will be executed regardless of who has logged in (including yourself, as Administrator).
Alternatively, I have prepared a downloadable registry file which will achieve the same thing. You can only merge this file into the registry from within an administrative account.