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PC turns on boot wont boot

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December 22, 2011 8:47:31 AM

Hi everyone i have just built a new gaming PC however after finishing the build it wont boot properly. The case fans turn on, the graphics card fan turns on, psu fan turns on and the dvd drive light flashes. However there is no beep when i turn it on and there is no display on screen.

I did notice that my motherboard has a 4 pin atx 12v port but my PSU has an 8 pin atx 12v so this port has been left untouched. Could this be why my PC isn't booting?, is not having anything in the ATX port prevent the CPU from turning on?

Thanks for any help in advanced, please can someone help asap as it needs to be working for christmas.

Heres my spec:

Asus m5a88m motherboard
Amd phenom 2 x6 3.6ghz
12gb corsair xms3 1600mhz ddr3 RAM
Sharkoon t9 case
Hitachi Deskstar 1TB Hard Drive SATAII 7200rpm 32MB Cache
LG GH22NS50.AUAA 22x SATA DVDRW Drive
Corsair CMPSU-600CXV2UK Builder Series 600W Power Supply
Sapphire radeon 6870 1gb GDDR5

Btw this is my first build

More about : turns boot wont boot

a c 78 B Homebuilt system
December 22, 2011 8:55:16 AM

The 4 pin port near to the processor is where the processor gets its power from. If you do not have anything plugged into it the computer will never be able to wake up the processor which is necessary to wake up every other part on the computer.

It is potentially possible that you can insert the 8 pin in the 4 pin slot and leave 4 pins hanging off the side. The keys are the same for the first 4 pins on an 8 pin and the 4 pins on a 4 pin in order to ensure backwards compatibility to the greatest extent possible.

It wouldn't look pretty and its possible the PSU maker didn't build the connector such that it is able to be inserted in a 4 pin slot, but it wouldn't hurt to try at least.

The worst that you can do is try to insert it and it doesn't work and you need a new PSU anyway.

The right orientation of the 8 pin will have the 4 pins on the end not using the 4 in the middle. If it doesn't go in with the 4 on one side then turn it around and try it with the 4 on the other side.

Either that or just look at the keys to determine which way it goes.

If you find the right orientation and the 8 pin cord is built correctly it should slide right in very easily. If it is the wrong way it will be very hard to make it go in so you will know if you are doing it wrong.
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a c 78 B Homebuilt system
December 22, 2011 9:19:16 AM

You could also go that route if you want.
a c 122 B Homebuilt system
December 22, 2011 10:22:22 AM

You do not need to buy any adapters. The Corsair PSU's use a "4+4" CPU power plug. Separate them and either half should fit. You want the yellow wires facing the edge.

Because this is your first build, look at the following threads.
Build it yourself:
http://www.tomshardware.co.uk/forum/274745-13-step-step...

And although this primarily a troubleshooting thread, the first part contains a checklist that will catch most noob mistakes:
http://www.tomshardware.com/forum/261145-31-read-postin...

And I recommend breadboarding a new build although, in your case, it may be a little late for that :)  :
http://www.tomshardware.com/forum/262730-31-breadboardi...

It doesn't take long, and it lets you test your parts before you install them in the case.
a c 78 B Homebuilt system
December 22, 2011 12:54:48 PM

Minor correction, only one half will fit, not either one.

If you can separate the connector into two separate sets of 4 then only one of the two will fit, the other will not fit regardless how you orient it.
December 22, 2011 5:45:35 PM

well thanks people ive split the 8 into two fours and plugged it in. However the PC still wont boot. :( 
a c 78 B Homebuilt system
December 22, 2011 6:27:46 PM

I guess I was mistaken, even though the keys are different you actually are able to plug the wrong one in if you are willing to overlook the correct keying.

For people that put square keys in square holes and round keys in round hoes, it will only work one way. Those who put round keys in square holes can apparently do either one.

My fault for following the keys.

Anyway, disconnect everything from the motherboard except the two times the PSU plugs into the motherboard and leave the RAM and Processor in.

Pull out any video cards or other discrete cards plugged into the motherboard and disconnect hard drives and everything from both the power and the motherboard.

Then try to turn it on. You can leave the power switch plugged in to make this easier if you want.

Tell us how that turns out.

If you don't get any response like that, then you will have to take the PSU and motherboard out of the case and put them on a wooden table and connect the PSU to the motherboard again (twice). Then try to turn it on by shorting wires. If you don't know how to do this you can search for it if you like. You should just be able to put a flat metal screw driver across the two power pins that connect to the PSU power button.

Let us know how that turns out too if you get that far.

Also, I can tell you right now if you didn't use the standoffs then it won't ever work. They have to be in the case or the motherboard will short every time you try to turn the power on.
December 22, 2011 8:55:59 PM

Hi i have used standoffs and also early today i tested the motherboard, cpu and fan outside of the case and it just turned on but didnt boot. As for the four pin connector i made sure the squares went in the square ports and the rounded ones matched up with the rounded ports.

Again thanks for all the help you are giving me on my problem.

There's probably something simple that i have missed because im a computer building noob. Just gutted i can't get it working as the PC is my christmas present.
a c 78 B Homebuilt system
December 23, 2011 8:31:53 AM

I am sorry you are having such problems too. It is nice when Christmas goes smoothly. There aren't many things other than computers built from individual parts that are so unlikely to work right out of the box.

Indeed part of the reason I am trying to help a lot of people atm is so they can have a Merry Christmas.

Anyway, do you have access to any other sort of computer parts for testing purposes?

Anything at all laying around or borrowable?
!