PC has no video out even with brand new RAM and mobo

Question

I have a computer which randomly one day had no display when I came in. I turned it off and back on, and it just kept restarting on me. Turn off, turn on, turn off, turn on.

Specs:

• Mobo: G41M-P25
• RAM stick 1 & 2:Patriot PSD34G1333KH 4GB PC3 DDR3 10600 CL9 2x2GB 1.5V
• RAM stick 3: Elite 4GB DDR3 1333 CL 9-9-9-24 1.5V (ALL sticks are unbuffered)
• CPU: Dual core E5500 2.5GHz
• HDD: 1TB 7200RPM Western Digital SATA
• DVD drive: Dell DVD-RAM 32x DVD Burner Drive (unplugged for all testing)
• PSU: CoolMax 600W PSU

I thought it was the power supply, and I went out and bought a new one and replaced it, but it still did the same thing.

I took it back and put the old one back in, this time I replaced the mobo. Now the problem changed from endless restarting to no video and no USB power, which is strange. Usually strange problems = RAM problems, so I switched out the RAM sticks one at a time. One of them triggered USB power while the other didn't but no video out, so I switched to internal graphics card instead, and it worked. So my external graphics card doesn't seem to be working either.

Now I have a bad mobo, 1 bad stick of ram, and a dead GPU.

I bought a new stick of RAM online and I turned it on today with the new one in, aaaaand... no video out, but still USB power. I cleared the CMOS and tried multiple combinations of all 3 RAM sticks (the new stick is different brand but has the exact same specs including voltage, timing, speed, everything.)

Still only 1 of the sticks turns the video on, and that RAM stick works in either slot.

| stick 1 | good      | DIMM 1 | computer works                       |
| stick 1 | good      | DIMM 2 | computer works                       |
| stick 2 | bad       | DIMM 1 | no video                             |
| stick 2 | bad       | DIMM 2 | computer starts endlessly restarting |
| stick 3 | brand new | DIMM 1 | no video                             |
| stick 3 | brand new | DIMM 2 | no video                             |

Either stick 3 is bad, I suppose it could be the power supply but I unplugged the DVD drive just to use less power and still nothing was working. Then I tried unplugging the HDD too, and still nothing. I tried all 3 RAM sticks and all combinations of the RAM sticks as well.

Using 4 fans to cool the unit.

Do you have any suggestions?

Answer 1

What is the maximum RAM speed that your mobo supports? You may find that it can have a max of 1600hz, and your ram is 3000hz? It could be the amount as well, it may only support slots 1-2 or 1,2,4. My motherboard only supports slots 1-2, 1,3 or 2,4. Check all those factors and see if it makes a difference.