PC Upgrade -> Black Screen

[dining_cryptographer]

I just upgraded my old PC with a new CPU, mainboard and RAM, but after putting the components together, plugging everything in and starting the PC the monitor remains black (gets no signal). The fans go on, but there is no other sign of life.

I went through these threads but didn't find a solution:
http://www.tomshardware.co.uk/forum/328484-31-build-display
http://www.tomshardware.co.uk/forum/261145-31-perform-steps-posting-post-boot-video-problems

Unfortunately, my mainboard doesn't support system-speakers. Is there any smart way of debugging without the beep-sounds?

My setup:
CPU: AMD Athlon X4 860k
Mainboard: Gigabyte GA-F2A88XM-HD3
RAM: 4 GB Crucial DDR3-1600

PSU: Be quiet!, Straight Power E5 450W
As a GPU I tried my old GeForce 8800 GTS and a Geforce GTX 760.
The old components worked perfectly fine before. I also checked the voltage on the main plugs of the PSU and they all where fine (only the orange wires had ~3.65 instead of 3.3, could that lead to problems).

I heard that the mainboard was sometimes shipped with an old BIOS, leading to incompatibility with FM2+ CPUs (although I think that was already one year ago). Would this explain my situation or should the screen show something even with an old BIOS?

I would be really glad if someone could help me or give me any ideas on what else could be wrong.

 

[xapoc]

What if you use on board video and leave the other GPU disconnected?

 

[dining_cryptographer]

I have no on board video, since the 860k is only a CPU no APU.

 

[dining_cryptographer]

I just noticed that on my old mainboard the PCIe slots have a seperate 12V power supply, which I can't find on the new one. Did I miss something or did they become more efficient/get the power from somewhere else?

 

[xapoc]

its because new video cards are more power hungry over the older predecessors.

 

[xapoc]

Went I checked your MB spec it says it has a APU chip on it.

APU with integrated AMD Radeon HD 8000/7000 series graphics

but did realized it still needs APU support from the CPU
* To use the onboard graphics ports, you must install an AMD APU with integrated graphics

 

[dining_cryptographer]

Ok, so if I got it right the "missing" PCIe power supply shouldn't be a problem either.

The only clue I have left is the story with the old BIOS. Do you know whether a PC with old BIOS (incompatible with the CPU) will get far enough to show something on the display?