I've just built my PC and it won't BOOT!

[absic]

It is really amazing just how many times this comes up on the forum. You've spent a small fortune on your CPU, RAM, Motherboard Graphics Card, PC Case etc go and connect it all up and..... it doesn't work!

The first thing you do is check all the cables are connected, still nothing.
You rip everything out and replace them all one by one.... .still nothing.
Must be a problem with the motherboard, CPU, RAM, Graphics Card.... right?

Well, being brutal, probably not. Have you stopped and thought of everything?
Really??
What about your PSU?
That's right the box that sits in the PC Case and supplies power to your system.

The majority of problems when building a PC, come down to the choice of Power Supply. If you consider that the CPU and RAM are the brains of your computer and that the motherboard is the skeleton then the PSU is the heart of it, pumping life giving energy to all of the components. In today's computers you need a good, strong steady flow of power or things just won't work properly.

It is no good spending all of your budget on your CPU, RAM, Motherboard Graphics Card and other parts without taking into consideration the power you are going to need to keep things running. Most motherboards require a minimum of 500 Watts and that's just for the basics. Having spent your money on other things it really isn't advisable to spend the least amount possible on your Power Supply.

A 500 Watt or less power supply might well be adequate for your needs but this should still be a good quality one not the least expensive. It should also be the minimum that you are looking at, especially if you are considering adding extra hard-drives, High End Graphics Card, DVD/CD Burners etc. You should actually be looking at 650 Watts as a minimum for most of today's PC's.


Things to look for when considering your Power Supply:

Does it have a Single rail or multiple rails? You are better off with a single rail that supplies enough Amps rather than two or more rails supplying the same power across them equally.

Does it have all of the necessary connectors? Most modern motherboards need a 24 PIN ATX connector and also a 4 or 8 pin ATX 12V connector. If you are using a high end CPU and Graphics card you really need to connect an 8 PIN ATX 12V connector to supply enough power for your CPU and Graphics Card's PCI-E slot, if your motherboard has this connection type. Also you may need extra PCI-e power connectors for your Graphics Card(s) so check that your chosen PSU has these. Although you can get away with using adaptors this adds another possible area for problems to occur.

How does it compare with other Power Supplies? Do your research. Often a quick search on the internet will provide you with all the information you need, as to how good a certain make of PSU is.

Does it come with a good warranty? Look for a PSU with at least a 3 year warranty, if you do encounter problems with it then at least you know you're covered.

Remember that, over time and with normal usage, the power supply will decrease in efficiency. Just because it worked in your old system doesn't mean it is good enough for your new one.

Where possible, buy a PSU with a higher rating than you think you actually need. This will allow for future expansion and will also give some leeway for the natural decrease in efficency over time.

[Dark Mantis]

Excellent advice absic, let's just hope that many people read and take notice of it.

I would like to add that very many problems on  the forum are produced or at least compounded by the use of very low end           ( the technical term is ...CRAP) PSUs. A lot of money is often spent on all the other components and then wasted on a cheap power supply which puts everything else at risk.

[virtualcrowbar]

Guilty! 

I bought a PC Case with a PSU supplied for under £35.00 and thought I had got a really good deal. Built my PC an it wouldn't start, apart from a couple of the fans spinning.

It took me ages to find out that the PSU was faulty and I RMA'd it. Got the replacement and the same thing happened!!

I now have a Corsair 750 Watt Modular PSU..... lesson learnt...... but I blamed everything else at first.

[Dark Mantis]

Yes that is another thing that a lot of people don't realise that they need a decent output and still think that a 350W like they had in their old machine will do  

[kaly422000]

very good advice . but in country like india people usualy spend  psu costing not more than 10$. i have 2 systems  running  with such psus(no problem as such with them)
but a recent purchased system built with H61M-DS2  has also that cheap psu.
the old 2 dual core (first generation  intel cpu)  SYSTEMS  working ok but  latest buy of h61m-ds2 based system  has some booting issue  some time.
some time during booting ,system  starts and stop and restarts twice or thrice for couple of seconds then finally boot.
me not technical.
but is it mother board problem(may be bios).
i am worried as it is new system

[Dark Mantis]

Hi

I would suggest trying a better power supply as a first course of action. If that doesn't help then try clearing the CMOS and load Optimised BIOS Defaults next.

Instructions for clearing the CMOS :

Remove the power cable from the mains supply and then press the power switch on the case for a few seconds just to drain any residual energy in the PSU capacitors.

Once done remove the motherboard battery overnight  or for one hour before replacing it.
 
Next plug back into the mains supply and boot.
 
You will now need to enter the BIOS by pressing DEL and load Optimised BIOS Defaults.

Make any other changes to the BIOS settings to suit your self like disabling the floppy drive, disabling the full screen logo and making the HDD the primary boot device and then press F10 to save and exit.

[kaly422000]

thanx sir for help .just noticed today ur reply as i had no email alert.any way actually what happen  during some booting is that,  i see dual bios uefi header in a blue type of screen ,instead of usual gigabyte logo and system stops(front indicater led,cpu fan and powersupply fan) and then it restart with front leds on and cpu fan etc. this start and and stop happens twice or thrice before finally boot. after booting  no such problem
and this booting problem occurs intermittent,means eg 2 out of 10  booting.
i purchased the mother board ,with intel g630 cpu,hdd 500 gb seagate and corsoir value select ram 4gb( 1 module)   with in 1 and half month.
these details as i give to make u understand.
if u can confirm that it is not a motherboard issue and replacing psu and clearing cmos will do. thanx in advance.

 to mention some time if restart immediately after shut down this  booting problem some time happen again.

[Dark Mantis]

As with many things it al boils down to a process of elimination. Normally you try the most likely and work through the list. Also it makes sense to try everything that doesn't cost you money first.   So make sure that the BIOS is up to date and the CMOS is cleared, then check the memory using Memtest86+ before doing anything else.

[lauradoom]

Not sure if this is a generic issue or just me having difficulty locating my cognitive equipment...
The new system I've just finished torturing into compliance refused to complete a POST when all 4 memory slots were filled. After going through the usual paranoid histrionics, I recalled memory-related issues when upgrading a previous system, and having removed two sticks, it booted. After loading o/s and board/chipset/hardware drivers, i booted to bios->M.I.T.->Advanced Memory Settings and enabled XMP (profile1), shut down, reinstalled the two sticks previously removed and full RAM was recognized by bios and o/s. The XMP setting also allowed memory to run at the advertised 1600 rather than the default 1333. 
[GA-Z87-HD3 - F2 bios - Corsair Vengeance 1600 MHz]
Is this a common problem, or am I a victim of my own incompetence? [Or both :]

[kozybaby]

 GA7170X 64 gigs of RAM I am using a Corsair 750 power supply

It is really amazing just how many times this comes up on the forum. You've spent a small fortune on your CPU, RAM, Motherboard Graphics Card, PC Case etc go and connect it all up and..... it doesn't work!

The first thing you do is check all the cables are connected, still nothing.
You rip everything out and replace them all one by one.... .still nothing.
Must be a problem with the motherboard, CPU, RAM, Graphics Card.... right?

Well, being brutal, probably not. Have you stopped and thought of everything?
Really??
What about your PSU?
That's right the box that sits in the PC Case and supplies power to your system.

The majority of problems when building a PC, come down to the choice of Power Supply. If you consider that the CPU and RAM are the brains of your computer and that the motherboard is the skeleton then the PSU is the heart of it, pumping life giving energy to all of the components. In today's computers you need a good, strong steady flow of power or things just won't work properly.

It is no good spending all of your budget on your CPU, RAM, Motherboard Graphics Card and other parts without taking into consideration the power you are going to need to keep things running. Most motherboards require a minimum of 500 Watts and that's just for the basics. Having spent your money on other things it really isn't advisable to spend the least amount possible on your Power Supply.

A 500 Watt or less power supply might well be adequate for your needs but this should still be a good quality one not the least expensive. It should also be the minimum that you are looking at, especially if you are considering adding extra hard-drives, High End Graphics Card, DVD/CD Burners etc. You should actually be looking at 650 Watts as a minimum for most of today's PC's.


Things to look for when considering your Power Supply:

Does it have a Single rail or multiple rails? You are better off with a single rail that supplies enough Amps rather than two or more rails supplying the same power across them equally.

Does it have all of the necessary connectors? Most modern motherboards need a 24 PIN ATX connector and also a 4 or 8 pin ATX 12V connector. If you are using a high end CPU and Graphics card you really need to connect an 8 PIN ATX 12V connector to supply enough power for your CPU and Graphics Card's PCI-E slot, if your motherboard has this connection type. Also you may need extra PCI-e power connectors for your Graphics Card(s) so check that your chosen PSU has these. Although you can get away with using adaptors this adds another possible area for problems to occur.

How does it compare with other Power Supplies? Do your research. Often a quick search on the internet will provide you with all the information you need, as to how good a certain make of PSU is.

Does it come with a good warranty? Look for a PSU with at least a 3 year warranty, if you do encounter problems with it then at least you know you're covered.

Remember that, over time and with normal usage, the power supply will decrease in efficiency. Just because it worked in your old system doesn't mean it is good enough for your new one.

Where possible, buy a PSU with a higher rating than you think you actually need. This will allow for future expansion and will also give some leeway for the natural decrease in efficency over time.