Take the 2-minute tour ×
Super User is a question and answer site for computer enthusiasts and power users. It's 100% free, no registration required.

I've been in the chat for the past while and found nothing so I figured I'd come to the front page.

For about 6-8 months I've had issues with my computer not starting when it was cold and even then when I plugged to many USB devices or a ethernet cable, it crashed, we eventually deduced the Power Supply was on its way out, so I order'd another one with almost exact same everything with the exception mine was 20+4 pin and this one is 24+4 pin, http://i.stack.imgur.com/5qpgb.png (Not actual hardware pictures just a diagram provided in chat).

Now with this one, warm or cold the machine has the same result, fan turns on, disc drive turns on, hard drive turns on, but the beep you'd get after everything powers on just before start is no longer heard, the screen receives no input and assuming it was perhaps a graphics issue, no audio you'd hear at start through the speakers is not heard.

If you place a disc in the drive, the drive clearly reads the disc.

EDIT: The Power Supply is ATX-250PA (1) FSP Group 250W 24 Pin and the desktop is ACER AM1100-E1401B.

EDIT 2: Copied from chat for a bit of ease, regarding issue with former PSU, displaying that the system does indeed start up. Ok me and Hennes have the same issue so I figured I'd do the testing, when our PSUs are cold the computer wont start, just tries, if we warm them up such as cranking the heat or using a hair drier to blow into the side vent for a min, they start up, with the exception of if you plug in to many USB devices it crashes and if plug anything into the ethernet port it crashes (just mine), so we deduced the psu was on its way out, since the USB ports draw about 1/6 of the power the ethernet adapter uses, we deduced the psu may not be able to put out enough watts for the system to run correctly, that and or there is a bad connection in the psu causing part of the problem (the whole warm/cold bit).

share|improve this question
    
Did you plug in the 4-Pin (12v) rail on the motherboard near the CPU? have you tried reseating the P8 (20/24 pin rail)? –  Frank Thomas Feb 26 '13 at 20:54
    
Updated info for further answers, –  user88311 Feb 26 '13 at 21:04
    
What exactly is your question? You seem to have figured out that the PSU is the problem. –  terdon Feb 27 '13 at 2:28
add comment

2 Answers 2

up vote 6 down vote accepted

Its super common for people to forget to plug in stuff - specifically your CPU power (4-8 pins, near your CPU), or your GPU power. Check your motherboard manual, locate it, and make sure its plugged in. This happens amazingly often, so its the first thing I'd check

The CPU power connector is usually a 4 pin molex connector, or a 8 pin molex connector that may be splittable. Look for something like

enter image description here

or

enter image description here

This should plug into something like this - this is on the OTHER end of the board from the 24 pin connector

enter image description here

Assuming you have a discrete GPU, you also want to check its power connector, assuming it has one. This is usually 8 pins, but more powerful cards often have a 6 pin connector as well. This is always at the top of the card, and the connector looks like this

enter image description here

share|improve this answer
    
and in my case, I had no clue I had to plug it in :D –  Sathya Feb 27 '13 at 3:22
    
Been there, done that, got the T shirt ;p –  Journeyman Geek Feb 27 '13 at 14:09
add comment

Considering your power supply is brand new, the problem is most likely with your motherboard. The way to test this is to remove all addon cards, hard drives, peripherals etc and try and boot your computer with just a CPU, ram and graphics card (if you don't have built in video on your motherboard). If you do have built in video, remove gfx card too. The objective is to have the least possible components that will still allow your PC to boot.

Listen for beep codes or look for error code LEDs etc on the motherboard. These will give your a starting point as to what is wrong. You will need your motherboard manual here to help identify beep codes or hex codes etc.

In these situations I find it useful to do a full BIOS reset too after having removed all peripherals.

I often take out all RAM besides a single stick. Sometimes I even take out all RAM and listen to ensure I get the "memory error"/"no memory" beep code. Once I know that the motherboard at least recognises it doesn't have memory, then I put a single stick in and see what other beep codes I get.

From this type of testing you can determine whether the motherboard is stuffed, or whether it is something else (like an addon card, drive or maybe a single memory stick). Unfortunately, testing your CPU and RAM require you to have another working and compatible computer to test them in.

Note that this process can be long and time consuming. If you find that you still get no joy after doing all this, you will have to individually test CPU and motherboard in known working computers to determine which is broken.

Sometimes if your computer is old, it is not worth the effort.

If you are lucky though, you will find that computer boots fine without say its gfx card and this may show you

share|improve this answer
    
The psu is used off ebay. Also please read all information before answer, generic answers aren't appreciated. –  user88311 Feb 26 '13 at 21:12
3  
What kind of answer did you expect? You're going to have to guess and check. –  Tanner Feb 26 '13 at 21:20
    
My answer is not generic. You likely have a motherboard problem. My answer describes how to determine exactly what is wrong. If you had a power supply problem nothing in your computer would turn on –  Devin Feb 26 '13 at 21:21
    
Updated, review if you will. –  user88311 Feb 26 '13 at 22:04
3  
yeah, he'd forgotten the CPU power connector –  Journeyman Geek Mar 5 '13 at 19:46
show 1 more comment

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.