How to make laptop boot to external monitor

[Dandi Rilo Pambudi]

My Notebook screen is broke, because of that I use external monitor, success but booting process does not show. One day When I got little problem with rundll32.exe virus. Other site command me to switch into safe mode for secure. But because boot process does not show, I can't press F8 in time to get my notebook to safe mode. I try again until can, And when I press and hold F8 on boot. desktop screen doesn't show. Maybe boot process still run at that time. I don't know the situation because I can't see what's happening on boot. Please help me???

 

[i7Baby]

I have a feeling your laptop doesn't know there's an external monitor plugged in till it loads windows.