Need help computer turns on but black screen at boot up

So my friend called me over to get assistance with building a computer. Everything was working perfectly fine with no issues. 5 days later he calls me up and tells me when he turns on his computer nothing appears on his monitor. Also he believes he is having issues with the RAM on his PC as DRAM light on his mobo is red indicating there may be a problem with the ram.

I tell him if he believes its a ram issue to simply turn off the PC. Once the pc is turned off to check and make sure the RAM is properly seated.

He told me he removed and reseated all the RAM in his system and this appears to have resolved the issue. When I arrive at his home his computer is running just fine and he is currently at his desktop in Windows 7. To ensure there are no problems with the RAM I have brought with me the latest verison of memtest86+ burned to a bootable cd.

He puts the cd into the drive and we shut down the system completely down by going to the start menu and hitting shut down.

The system shuts down properly. We wait a few seconds and then press the power button on the computer. You hear the computer power up. All the fans are running but nothing appears on the monitor. I listen for any beep codes but nothing occurs and the screen is pitch black. Wait a few more minutes and nothing. We then completely turn off the system. Disconnect the power supply from UPS and wait some more. We see the mobo power light which is normally green goes off indicating there is no power to the board. We plug the system back to the UPS. The green light is back on indicating there is power. Turn on the system and same thing occurs (Black screen, fans spinning, no beep codes).

Due to time constraints I had to leave and could do much more for troubleshooting as I had to be somewhere else.

I am looking for some help as to what the problem could be and what steps I can take to resolve the issue.

Below is specs of the computer parts my friend is using:



CPU: Intel Core i7-3930k
HSF: Noctua NH-D14 SE2011 or Thermalright Silver Arrow,Archon,TRUE Spirit 120
MOBO: ASUS SABERTOOTH X79
RAM: Corsair Vengeance LOW PROFILE:#CML16GX3M4X1600C8

GPU: MSI N560GTX-Ti Twin Frozr II 2GD5/OC - (I'm pretty certain he changed this to a 570ti msi card but not sure yet)
HDD: Seagate Barracuda
SSD: Crucial M4 128GB (3.5" drive adapter bracket) CT128M4SSD2BAA
ODD: Pioneer BDR-206DBK
PSU: Enermax Platimax 750W
CASE: SilverStone FT02B w/USB 3.0,Air Penetrator Fans
KB: SteelSeries 7G
MOUSE: Logitech G9X laser
MONITOR: Samsung LS27A850DS/ZA
UPS: Tripp Lite SU1000XLA
OS: Windows 7 Ultimate Retail Box

I would run on 1 RAM stick and try all 4 of them to see if 1 is bad.

Thank you for help. I will try the memory sticks 1 at a time to see if its a memory issue and also try clearing the cmos using the jumpers as indicated in the manual.

However if this fails to fix the problem what would be the next step. I have some feeling its not a memory issue but a display issue. When the power button is pressed the system turns on. The fans are running, the keyboard lights up (caps, num lock, etc), the board has power just nothing comes on the screen. I turn off the monitor and back on and it shows searching for signal. The system was working fine 5 days ago. Before pressing the power button would power the system. The monitor would display the ASUS Sabertooth Bios Splash screen prompting that if you want to go into the bios press delete. If delete was not pressed it would load Windows 7 and ask us to sign into the desired Windows 7 account. So its kind of puzzling.

If you have any other suggestions or things I can try or check that would be a great help.

i had the same problem. but i checked the cpu fan was loose. and i had put too much thermal paste.

OK, so I understand now... Do u still have the black screen or not?