fn + F5 not working for external monitor

Posts: 1

fn + F5 not working for external monitor


I have old Toshiba Satellite L35 S2161 model laptop and recently bought Viewsonic VX2450WM-LED Monitor with Full HD 1080p, connected laptop to external monitor with VGA cable but when I turn on the laptop the monitor screen shows windows xp professional at the boot and then the monitor screen goes blank and displays message "NO SIGNAL", and windows is launched on the laptop screen. I have tried Fn+F5 keys to change the display to laptop, but nothing happens. Also, tried changing the display resolution which didn't help. I am able to extend the display to viewsonic monitor but thats what I don't want to do, I want to make ViewSonic as primary monitor.


Also, tested with Dell laptop and I was able to switch the display to ViewSonic monitor.


Can someone help me, I am running out of options to fix the problem.