This program will disable your LCD or monitor when executed. Useful for conserving battery, screen life, and privacy. Very handy for overriding software that blocks the automatic screen powerdown (like Synergy).
It should work on fairly old systems, back to Windows NT 3.1 and Windows 95, unlike the C# versions elsewhere. It is also 7.5kb vs 85kb.
I recently upgraded my trusty ThinkPad T42 to Windows 7. Unfortunately, the screen-off keystroke no longer works. Some quick Googling showed that people made their own handlers in C#. Well, that sucks if you don’t have the .net CLR. This is not a problem on Windows 7, but I also wanted to try out my Assembly skills since they were all just calling standard Win32 APIs.
TITLE Monitor Off (main.asm) ; Description: This program turns off your monitor (power saving mode) ; Revision date: 2 November 2009 INCLUDE Irvine32.inc INCLUDELIB Kernel32.lib INCLUDELIB User32.lib SendMessageA PROTO :DWORD,:DWORD,:DWORD,:DWORD GetConsoleWindow PROTO WM_SYSCOMMAND = 0112h SC_MONITORPOWER = 0F170h OFF = 2 .data msg BYTE "Monitor off. Program from Kev009.com",0dh,0ah,0 .code main PROC call Clrscr ; Get our window handle to send the event to INVOKE GetConsoleWindow ; The handle is now in eax INVOKE SendMessageA, eax, WM_SYSCOMMAND, SC_MONITORPOWER, OFF mov edx,OFFSET msg call WriteString exit main ENDP END main