I just upgraded my computer to a new motherboard , new moniter...everything is fresh and brand new, even a brand new 300 watt power supply (ATX) and the thing was working perfectly up until today for NO DAMN REASON AT ALL!!!!! (yes I'm frustrated) I just went to turn it on and nothing happens. Its not the power cable, its not the power switch, its not the wall socket, I checked everything, what the hell could it be????!? Just before it did this the computer would turn on but the moniter wouldn't display anything, so I discharged the CMOS jumper thingy on the motherboard (abitKt7araid board). heeeeeeeeeeeeeeelp I'm stuck using my old POS computer that doesn't even have a working sound card (sound sticks on).
Chris

I HATE computers.

 

Looking at the fan on your power supply, does the fan turn at all when you flip the switch on the back of the power supply?

 

If it turns, the power supply is fine. If not, assuming it's plugged in and everything it may've gone out for whatever reason because i've never encountered a working power supply that didn't have a fan that twitched or moved slightly when the switch was flipped.

If that's good, try reseating the memory modules. Just pull em out and put em right back in. That's gotten me a few times. If it still doesn't work, if you have more than one try inserting one and not any others. Play with that for a little bit and see if anything happens.

If it still doesn't work, try reseating the video card. It should beep at you if it's not in there right, but you never know.

You did get a fan and heat sink for the new processor right? Double check the jumpers and don't fool with overclocking.

 

video card was my first guess too, but you didn't mention beeping. Do you have a rocker switch on your power supply? does your old computer have an agp by chance? You could see if your vid card just took a dump on you

 

I worked on a computer that had an on board harddrive controller that sheet on itself... it acted similar.

 

Most modern power supplys do not have a power switch which actually makes and breaks the power connection directly - they have a switch which "tells" the supply to come on by completing a circuit. Try unplugging the machine and leaving it unplugged for several minutes and then plugging it back in. You should get a spark at the plug. This is the caps in the power supply charging.
Then try turning it on a again.

If this doesn't work, you are about to have a lot of fun :-).

First thing you need to be aware of is that there is a wire going back into the power supply on the motherboard power connector which is the "power good wire". This lets the power supply know that the motherboard thinks power is within parameters. Without this signal the supply will not put out power for more than an instant. Thus you can't usually power up the supply without it hooked to a motherboard to measure its voltage. Fan running is a good indication that the power supply is up as someone has already noted.


Your next indicator is the trusty beep as the machine boots up. If you are not getting it, yank every board from the motherboard and pull power connectors from everything but the motherboard (including the drives). Then try to power up the machine. If it doesn't beep you have got a major problem either with the processor/ BIOS/ motherboard or with the power supply.

If it DOES beep, start replacing boards one at a time (video first) and then repowering and trying again until it doesn't beep thus identifying the culprit. If it still beeps after the boards are all in, then start with the drives. This process, alas, has been pretty much standard troubleshooting procedure since the dawn of PCs.

Once you have the hardrive on which your operating system is located powered up, don't go much past the beep with your testing untila all the hardware you can run with the machine booing is installed or Windows may start thinking stuff you want there isn't there anymore.

Let us know what you find.