Wont boot after re-assembling.

[JustJohn101]

Hi, yesterday i took all of my pc apart to clean it all an manage some wires. I have done this many times and as always i wore my anti static wrist band and took all the usaul precautions. 

On assembling it all again i turned it on and it would continuously start up and turn off with no display untill i turned the psu switch off. I searched alot and tryed all the suggestions. If i start up with no ram at all then it stays powered on with no display. Ive tryed 3 different sticks off ram 1 at a time in dimm 2. Ive reset cmos and tested the voltage on the batt. Ive tested the psu. Took out both hdd and ssd and tryed to boot from onboard graphics. 

It has happened about 5 months ago aswell and taking one stick off ram out fixed it that time, but ive tryed an older stick off ram thats sat in a box for about a year and should be fine. Could anybody give me any advice it would be greatly appreciated. 

Specs. 
Cpu-I7 4790k
Mobo-Msi gaming 5
Gpu- msi r9390
Ram-kingston 1866mhz 16gb (2x8gb)
Hdd- seagate 1tb
Ssd- samsung 850evo 256gb
Psu- evga supernova 650w

[Alec M]

Is your cooler running?

My computer would turn on and then thermal throttle after about five seconds, due to my watercooler failing.

[Jasun]

Make sure, I mean MAKE SURE you have everything where they need to be, for example, put the gpu into the slot and make sure it's actually in the slot instead of hanging halfway. Check if there is anything stuck between the cpu and the socket expecially some thing metal because that messes with the cpu and the motherboard.

[xgn]

Did you put on the jumper caps and power connector ?

[JustJohn101]

Thanks for the replys. I have also removed and replaced the heat sink to check the cpu and replaced the paste. My mobo doesnt have a jumper just the 2 pin one to reset cmos. I have removed everything and the only thing that makes a difference is removing the ram. But a previously working stick doesnt work in it and the slots look fine as do the solders on the rear. 

[xgn]

Do you have any signals on the hardware? any lights on the mobo ?

[JustJohn101]

Yeah with any ram in it will turn on all fans spin up, all led's turn on and the hdd spins then it will turn of after 2-3 seconds then turn back on repeatedly untill i switch the psu off. With no ram in it stays powered on with no display.  

[Alec M]

Umm, you're getting no video, right?

 

[Alec M]

Also, have you plugged in your CPU power?

[JustJohn101]

Nope monitors (i have 2) dont even come out of stand by. And yes everything is pluged in. Ive also tryed removing all the front panel cables and starting by jumping the pins. 

[Alec M]

Are you connected to internal graphics?

 

[JustJohn101]

Ive just tried an old gpu and that didnt work either. 

[StunterX]

Seems like an cpu or motherboard issue, since you have changed pretty much everything else

[JustJohn101]

No i have tried display port, hdmi and vga on the gpu. I have tried to boot with the internal graphics to the same result. 

[Alec M]

Like we've all said, what CPU cooler do you have?

[JustJohn101]

I have a old cpu i could try but would the effect the os when i change bacn because i havnt got my windows key. 

[JustJohn101]

Sorry i have a cooler master hyper evo 212

[Alec M]

That should be fine even if you run it for a bit without the fan, how hot is it to the touch?

[JustJohn101]

Its didn't feel top hot the last time i checked it after running for a few minutes.  The coolers running fine. 

[Alec M]

Okay, did your motherboard get dropped, scratched or pushed on while doing the rebuild?

[JustJohn101]

No i took it out carefully using my anti static band and left it on my glass desk. Its was out for around 30 minutes. 

[Alec M]

Is your CPU seated properly?

 

[JustJohn101]

Yeah ive taken it out to check and all the pins look fine. 

[Alec M]

Do you have a M.2 SSD?

[JustJohn101]

No just a sata.