From onboard gpu to external through BIOS?

[Trillax]

Hello everyone. I have recently been doing a budget LAN pc.

The problem is that when i turn the system on, it boot just fint except my monitor does not recieve any kind of signal. I have tried different hdmi cables and have been trying with another graphics card, but without luck. The only way i managed to get a signal was to plug in my vga cable to IGPU on the motherboard controlled by my i3, meanwhile the gpu was connected and running.

The specs (currently):

I3 2100

Asus P8H61-M LX3 PLUS R2.0 (lga 1155)

4 gb ddr3 1333 mhz

Palit geforce gtx 660 (2048 mb memory)

350W psu modded with a 6-pin molex connector to a 6-pin pci express connector --->

standart micro atx case, unknown

I've already tried to reset the cmos, but without luck.

I've already looked into the BIOS settings and forced it to use pci express, instead of IGPU.

What other kinds of troubleshooting did i miss?

[MilfShake]

So chances are the GPU is broken, try different GPU

[Eric++]

This might sound silly but do you have the proper drivers installed? Otherwise I would check and make sure the Graphic card is firmly in it's socket. Verify that your system acknowledges it's there at the very least.

[Trillax]

So I have now tried with my gtx 1060 without any post either. The problem might be i don't have a operating system or even a harddrive installed, so i will try it out with windows soon, when my ssd arrives. 

[Trillax]

I also tried my 660 in my primary i5 6600k build and it worked just fine.

[Trillax]

Even my old Pentium D cpu is able to boot with the gpu. Sorry for the mess.