Help: Just built a computer wont turn on

[Poop_GoblinsXXX]

I just finished buiding my first computer and when i plugged it in nothing worked. Im pretty sure its my PSU because the fan wasn’t even running on that. I checked to make sure all the switches were turned on and i did it a couple times to make sure. Does anyone have an idea as to what the problem may be? Thanks for your help.

[Tevildo]

The first thing to check is that you actually have mains power. Plug something else (a lamp, for example) into the socket and confirm that it works. If it does, the next thing to check is the cable between the socket and the computer - again, plug it into something else that you know works (and which has a standard IEC mains socket).

If you are getting mains power, first check that there isn’t a mains switch on the back of the PSU that’s set to “off”. (There might also be a voltage selector - make sure it’s set correctly, if there is - but most modern PSU’s select the voltage automatically). If there’s no switch, or if there is a switch and it’s set to “on”, check your motherboard. There should be a light somewhere that goes on when the PSU is getting mains, even if the machine as a whole is still off. If you don’t get this, check the connections between the PSU and motherboard; if these are OK, then, yes, it’s probably the PSU. If the motherboard light is on, but the machine doesn’t start when you press the power button, check that the cable from the power button to the motherboard is connected to the right header - it’s quite easy to get it off by one pin, or connect it to the “reset” header by mistake.

If that isn’t the problem, remove everything from the motherboard except the processor - the video card, RAM, everything except the processor and the connections to the PSU and power button - and see if it’ll start then. If it does, put your components back in one at a time (switch off between replacements, obviously) - this should identify which one is bad.

[HMS_Irruncible]

@Poop_GoblinsXXX

I just finished buiding my first computer and when i plugged it in nothing worked. Im pretty sure its my PSU because the fan wasn’t even running on that. I checked to make sure all the switches were turned on and i did it a couple times to make sure. Does anyone have an idea as to what the problem may be? Thanks for your help.

The case has an on/off switch. This switch must be connected to the motherboard and then (obviously) turned on. Of course you must also turn on the PSU switch as well. Failing to do this would cause the behavior you described.

Also, failing to connect the power supply cables from the PSU to the motherboard correctly could cause this. You want to double-check your documentation and make sure you’ve done this correctly.

Try this and get back to us… also, tell us if there are any diagnostic lights on your motherboard, and while you’re at it, tell us what kind of motherboard you have.

[Poop_GoblinsXXX]

Thanks alot for your help. it turns out i forgot to press the power button on my case. im such a n00b

@Tevildo

The first thing to check is that you actually have mains power. Plug something else (a lamp, for example) into the socket and confirm that it works. If it does, the next thing to check is the cable between the socket and the computer - again, plug it into something else that you know works (and which has a standard IEC mains socket).

If you are getting mains power, first check that there isn’t a mains switch on the back of the PSU that’s set to “off”. (There might also be a voltage selector - make sure it’s set correctly, if there is - but most modern PSU’s select the voltage automatically). If there’s no switch, or if there is a switch and it’s set to “on”, check your motherboard. There should be a light somewhere that goes on when the PSU is getting mains, even if the machine as a whole is still off. If you don’t get this, check the connections between the PSU and motherboard; if these are OK, then, yes, it’s probably the PSU. If the motherboard light is on, but the machine doesn’t start when you press the power button, check that the cable from the power button to the motherboard is connected to the right header - it’s quite easy to get it off by one pin, or connect it to the “reset” header by mistake.

If that isn’t the problem, remove everything from the motherboard except the processor - the video card, RAM, everything except the processor and the connections to the PSU and power button - and see if it’ll start then. If it does, put your components back in one at a time (switch off between replacements, obviously) - this should identify which one is bad.

[Poop_GoblinsXXX]

thanks brain wreck

@Brain Wreck

The case has an on/off switch. This switch must be connected to the motherboard and then (obviously) turned on. Of course you must also turn on the PSU switch as well. Failing to do this would cause the behavior you described.

Also, failing to connect the power supply cables from the PSU to the motherboard correctly could cause this. You want to double-check your documentation and make sure you’ve done this correctly.

Try this and get back to us… also, tell us if there are any diagnostic lights on your motherboard, and while you’re at it, tell us what kind of motherboard you have.

[Aunt_Flow]

At least you didn’t do what I did when I first built a computer. Didn’t mount the motherboard on those bracket/spacer things and stuck it straight on the metal case. Couldn’t understand why the damn thing wouldn’t turn on. Luckily I did NOT fry the mb by the time I found out what I’d done.