Computer turns on but no video, no power to USB devices and no boot

[OrionMaster]

I'm having a problem with my desktop. When I turn it on, the light of the on/off goes green, the CPU fan starts but there is no video output (i tried both VGA and HDMI, even USB), there is no beep sound of any kind, no boot (no windows sound) and all my USB devices connected to it get no power (keyboard has no lights, mice has no laser underneath). It doesn't look like the power supply given that the fan is running normally and the lights go on. Could the motherboard have fried? How can I make sure thats the case?

 

[VirtualLarry]

Specs of Desktop, and age? Was it recently moved, bumped, or vacuumed? Did someone spill a drink over it and not tell you? Any recent storms or electrical disturbances?

Can you unplug all of the USB devices, and see if it boots?

You might consider unplugging it completely from AC power, and take off the side panel, and look for bad capacitors. They are little metal cylinders that store electricity. With age, temps, and abuse, they can fail. In fact, they are generally the first thing to fail on a motherboard. (Besides VRMs, when overclocking.) Look for bulges out of the top, or discoloration.

Btw, has this PC ever been overclocked?

 

[Ketchup]

Does the computer normally have a POST beep? Had you done anything to it between boot and no boot?

Unplug anything that isn't necessary (really only need video, cpu, ram at this point) and see if it boots. If you CPU or motherboard has integrated graphics, remove a video card from the mix. If you have not performed a CMOS reset yet, now would be the time to do it.

 

[OrionMaster]

2 year old machine
Motherboard Asus P8B75-M LX
core i3 3rd gen
12GB RAM Kingston
The only thing I did recently is that I stopped using it daily. I switched to a macbook pro. Previously, I used to use virtually every single day for 2 years

 

[VirtualLarry]

Hmm. That's new enough that the caps should be OK. It may well have solid caps too, which should last 10+ years.

I would remove all the RAM, and then try one stick at a time, and see if it boots. Sometimes thermal stresses can dislodge RAM.

 

[OrionMaster]

I did you guys suggestions and I was able to boot briefly once when I unplugged the RAM and put it back in and unpluged all the SATA cables. But after that, it stopped working (even without the SATAs). Now not even the CPU fan is starting (its like it tries but then it dies). It must the the power supply because the video output worked that time

 

[PhIlLy ChEeSe]

2 year old machine
Motherboard Asus P8B75-M LX
core i3 3rd gen
12GB RAM Kingston
The only thing I did recently is that I stopped using it daily. I switched to a macbook pro. Previously, I used to use virtually every single day for 2 years

Well there you go, its mad at you!
Try removing the battery and doing the jumper to clear Coms? Also try an over night one as well. Or another PSU? Try using a different GPU? OR a different PCI-e Slot?

 

[OrionMaster]

I figured out and solved the problem. The power strip was overloaded and couldn't supply enough power to the macbook, three external monitors, DSL modem, PC and ventilator at the same time. I'm using another strip from another plug and it booted just fine. Silly me

 

[VirtualLarry]

I figured out and solved the problem. The power strip was overloaded and couldn't supply enough power to the macbook, three external monitors, DSL modem, PC and ventilator at the same time. I'm using another strip from another plug and it booted just fine. Silly me

"Ventilator" == fan, or "air conditioner"?

 

[OrionMaster]

"Ventilator" == fan, or "air conditioner"?

Air conditioner

 

[Ketchup]

I figured out and solved the problem. The power strip was overloaded and couldn't supply enough power to the macbook, three external monitors, DSL modem, PC and ventilator at the same time. I'm using another strip from another plug and it booted just fine. Silly me

Nice detective work!

 

[OrionMaster]

Nice detective work!

Actually, nevermind my suspicion that it was the power strip. It wasn't. It was a bad stick of RAM that was preventing the system from rebooting. It just so happened that I switched the slots before I changed the power strip (2 sticks). The computer stopped detecting the bad RAM when I did that and started to boot, leading me to think it was the strip. When I saw that the RAM dropped from 12GB to 4GB I switched it again but the problem came back. Only way to boot is to remove the stick now. 8GB of RAM lost, damn

 

[Ketchup]

Ha, it happens. At least most RAM has a lifetime warranty.