New FM2 computer, no display output

[Peruzzy]

Newly made computer :

APU FM2 AMD A6-5400K
MB FM2 A75 MSI FM2-A75MA-E35
DDR3 4GB RAM 1866MHz
500W PSU

Today arrived, after socketing the CPU without problems and inserting RAM in slot, installed motherboard into the case.
Plugged in PSU to MB, HDD... tried turning on the computer, fans are rotating but nothing shows up on monitor.

Tried swapping RAM into another slot, same problem.

Checked if CPU is properly socketed, he is.

Unplugged HDD so I only had (MB, CPU, RAM and PSU) together (Enough to get me to BIOS) but no, nothing...

I have no idea what to do now.. :/

 

[alexoiu]

Is the CPU fan spinning? If yes, then test the board outside the case. Can you attach a case speaker to the motherboard?

 

[Peruzzy]

Problem solved, I forgot to plug in CPU power supply..
I'm so stupid