Can't boot without computer monitor

I am using a mac hachintosh as slave machine. So i do not have to connect a monitor to the system. But it does not boot without a monitor, once i hook a hdmi based monitor to it, i am able to boot fine but if i boot without a monitor, it does not boot.

I do not have a spare monitor. Is there anything i can do to boot into hachintosh with el capitan without a screen? I access the system via Lan screen share feature of mac.

My system is i7 2600k with hd 3000 graphics. Gigabyte gigabyte...

Can't boot without computer monitor