Reset BIOS of Aspire XC-115 ? I have a dark screen and blinking power button

I can't believe nobody has asked this question before sind I have googled it and it does not appear that uncommon.

I downgraded from Win10 and somehow I can't get the BIOS to give me options. The screen does not get a signal and all I get is a blinking power button.

Here is what I tried:

I disconnected everything - HDD, DVD, Power and removed the battery from the motherboard and waited 5 min

and combinations of the abover connecting something :-)

I believe I should reset the motherboard BIOS and frankly on the motherboard I encounter just three locations where I could manipulate things with jumpers. Is there a manual for the MB somewhere? A way I can flash a new firmware from a USB stick? Any trick to get the Monitor to show something?