Start reseating everything, power cords, ram, cpu, everything. From there just start swapping stuff back and forth, two sticks of ram? Try it with just one, then the other. If its still kaput after all of that you probably have a dead motherboard or faulty powersupply. 

 CPU fan is usually bios controlled once CPU reports temp from its thermostat to the fan controller.

No CPU fan means either dead bios or dead CPU, or other component fault drawing down a power rail.

No post fail or error message at all suggests motherboard but that depends on the vendor.

First check with multimeter all of the PSU rails while running and connected.

If PSU voltages bad, remove all power connections to PC, jumper the PSU motherboard enable pin and check again. If voltages ok without load, remove all components from motherboard, connect PSU and repeat voltage test. If bad, then a bad motherboard. If good, insert components until voltage is bad.

If you have a high speed oscilloscope you can try to check the PCIe bus for activity on startup and noise on the PSU. I don't know what equipment you have or spares for testing. 

 @verita84 :Debian_logo: :firefox: :bing: :android: ... 
hard to believe both are bad, there's probably a power cable that is not plugged into the mobo. it looks like you have stuff plugged in but check the mobo manual.