Computer starts up and nothing works

Hi All,

My sister in law sent me her computer to see if I could fix it. I am guessing the motherboard is bad. Everything starts and runs CPU, Fans, power supply etc but DVD and CD Rom will not open, monitor says no signal there are no beeps of any kind, all LED's light up, just nothing works. Any ideas? Could it be the motherboard or something else to cause it? I am stumped.

 

Interesting. How do you know the CPU is running? Sure, you can see the CPU fan spinning, but that's not the same thing.

In the absence of other information (like, what kind of a machine are we dealing with -- desktop/laptop/IBM-type/Macintosh/whatever), my first guess is that the power supply unit (PSU) is supplying voltage on the 12v rails but not on the 5v rails. That'll operate the hardware, but leaves the logic circuits with no power. The easiest way to test that possibility is to swap in a replacement PSU if you can. But keep in mind that a mobo short can draw the voltage on a given rail down so far it looks like the PSU is bad. (But usually, the PSU will shut down or fry when that happens.)

If swapping the PSU with another isn't an option, here are some websites that will help you test the output of your PSU:

<http://www.devhardware.com/c/a/Hardware-Guides/An-Introduction-to-Accurate-Voltage-Measurements/3/>
<http://www.ochardware.com/articles/psuvolt/psuvolt2.html>
<http://articles.techrepublic.com.com/5100-10878_11-5034541.html>

(And if your sister's machine is a Dell machine, keep in mind that Dell has used non-standard pinouts in the 20-connector plug, i.e., some of the connections have been swapped around. Voltages won't be where you expect them to appear in some of their machines.)

 

Hi,

Tray this link http://www.hardwaresecrets.com/article/547 .
Could help you !

 

Not to bash you link Mos_llie, but your article seems to deal with a computer not powering up when the computer receives the "power on" signal. pcgeek's computer is powering on (fans are spinning) but is not completing it's power on self test (POST), which is causing your computer to not boot or show an image.

This can be cause by almost everything, and process of elimination is key. I would start by taking your RAM out and putting it back in. This ensures a proper connection. If that does not work, try disconnecting all optical and hard drives. If that does not work, remove everything not necessary for the computer to POST: That is 1) Power Supply 2) Motherboard 3) Processor 4) RAM.

If you remove something and the computer suddenly boots, you will then know the offending device. If you computer will still not boot with only the PS, Mobo, Processor and RAM, Then you need to find yourself a test PS and test RAM. Make sure the test RAM is compatible with the motherboard by looking up the model number on the manufacturer's website. Replace the PS and see if it works. Then Replace the RAM and see if it works.

If after all of this, your computer still does not get past POST and attempt to start windows, I would say you have a bad motherboard or processor (probably processor). At this point, you could try the cleaning sections of that link Mos provided, but I would say replace the motherboard and processor.

Hope this helps. Make sure you always have the power unplugged when you remove something from the motherboard.

 

btw: Do not work on your computer on carpet floor. This can cause static electricity to build up and damage your computer.

 

I am sorry I forgot to say what the unit is. It is a desktop PC Gateway system but not sure which gateway machine it is because it foes not say anywhere on the machine. As far as the CPU fan I am just assuming it works (I know never assume) LOL . Thanks for the information I will keep plugging away with it. I do have a couple PSU's I can use so I will try that.

 

Thanks, I know that I use anti static mats.

 

Thanks Senlis. I have removed RAM and still nothing will try other things you suggest too. Thanks to both of you for the replies I will keep working away and post my results later.

 

Keep in mind, If you remove the RAM, your computer will not post then either.

I forgot the obvious. It is possible whatever graphics you are using has been damaged and is not working. Whether it is on-board graphics or a graphic card, you may try using a known good video card and seeing if that works.

 

If you try to boot without the RAM, the POST will fail at RAM testing. You should have a very unhappy beeping motherboard! If it does not beep like crazy with no RAM when booting, does it have a speaker hooked up for beep codes? Try another PSU as suggested above.

 

Yep: Mine isn't scientific diagnosis, just "whatever" hdware replacement idiocy...but:

Since a couple times I thought it was *monitor* when nothing happened, no visual post, nothing...and beeps kept coming,

I finally looked up what *Dell* had to say, and tried removing and re-installing RAM, and that *was* the problem..and has proven to be the problem on a friends computer, when we both thought it was monitor or even *modem* for some damned reason...

Second, it doesn't cost that much to have a spare PSU, or even CPU (I have pent4 I use for this)...and u don't have to put in the PSU, just sit it on top or off to side, and replace other PSU cables w/it, and check that out...tho that wasn't ever really my problem, I thought it might be....

Third, I pull off cpu fan/heatsink and replaced dreaded cpu, which can be interesting (I've learned to *love* thermal paste removal and application), just to see if that *is* the problem...and yeah, MS will usually catch you, and want u to re-register, but at least you'll find out...then u can go back to normal, or replace cpu, tho that, too, has never really been my problem...

Again, usually w/me it'll turn out to be something really basic, like a switch I forgot to turn on, or RAM I had jiggled loose, or a monitor not plugged in, etc...but I always want to think it's something more exotic, like master boot record, or failing HD, etc...but nah, not with me...I just have dreadful habit of overlooking the obvious...

Best wishes...

 

Hi All again thanks for all the replies. I got the computer up and running it was a RAM problem one slot is bad so I removed it and reinstalled the RAM in the other slots and it booted up just fine. I had to reformat the hard drive and now I need to reinstall the drivers for the computer. It is a GATEWAY GT5034 and I found the gateway site but not sure with all the choices they have what I need when I go into the device manager there is no information available under properties of each one. The list with the yellow question marks under other devices is as follows...

Multimedia Auto Controller
Other PCI Bridge Device
SM Bus Controller
Video Controller (VGA Compatible)

The above drivers are now missing and I am not sure where to find them under gateways list can someone help me? Everything else on the computer works perfectly just these things are missing.

Thanks in advance

 

gateway's website is a bit tricky. You should be able to click on driver downloads under support and then supply them with your serial number.

btw, I assume you put your good stick of RAM in the other slot to make sure it was the RAM slot and not the RAM that was causing the problems right?

 

Yep sure did! Thanks for the reminder though

 

I'm glad to hear it's working: that's happened to me, twice now...but it's actually a *plus* since now it's usually first thing I check on friend's computer, when they ask me to "take a look" and when I check RAM, and it *is* RAM, they think I am a genius!

Takes'em about 1/2 hr of watching me work on their computer, tho, to realize I don't know what I'm doing, after all, and will probably fry the damn thing, but hey , it's not my computer ;-)

 

LOL duckfeet I like your reasoning.

 

Bah, just ask them where their 1440 dial up modem is for emergency updates.

And ask them if they do full backups or sequential backups. When they go ahhh, tell them you will most definantly need to take the computer to your shop. :-D