PC NOT BOOTING!!!!

Just a quick thought...is there any activity at all in the computer? If when you push the power button nothing happens, open the case and see if there is an LED on the MB, usually near the RAM to see if power is even gettin to to the MB. If not then its hopefully an power supply issue, but at least you know the prob is either PSU or MB. Also check the power button on your comp..ive had one break and couldn't start anything unless i shorted the conncection.  

If you turn on the computer do you hear the fans running ?
Does it beep when you turn it on ?
Does the Light come on to the floppy drive ?
Try swapping the power cable off of your monitor with the one on the pc the power cable may have gone bad... if still nothing make sure the computer is plugged directly into a wall if not plug it direct to a wall try a lamp in the outlet to make sure the outlet is working. It may be possible the outlet went bad or power strip
if still nothing.....
You will need to either have a grounding wrist strap when you do this or maintain constant contact with the metal frame inside the case. With the computer plugged into the wall but the POWER OFF. Open the case of the PC without touching anything inside the case turn it on see if the fans are running at all inside the case if no fans are running you do not hear any activity on the hard drive or anything else moving cd-rom drive etc.... then the power supply is probably shot... If fans are working and or drives are moving, power off the PC while touching the metal frame in the case remove the video card and the ram. Turn the pc on see if it starts beeping.... if it does then the motherboard is recognizing devices and it may be your video card is bad... if it does not beep chances are the motherboard may be the problem to verify it even further you could remove the processor and then turn on the unit if no beeps but their is power to it then your motherboard is shot. Removing the processor will throw the motherboard into a panic of beeps so if no beeps then it is dead providing you have verified you are getting power and the power supply is good.

You say you've tested....(excuse me...) I mean checked every device component, and state that Everything is ok?  how do you know they are ok?  or what do you mean by OK?  and how did you test them?  

Swapped out parts that normally boot up and tested it in a different setup?  or what....like how did you test the motherboard...?

Sorry for all my questions, but you've seem to have "checked every device"  and state that "everything is ok?"  If that's the case, then either some components are not compatible with each other?  Or you've made a mistake in your checking.  I would try again, and give us a bit more detail on what you've tried or haven't tried....did you try spare parts?  does the LED power lights and such come on? and fans spin up?....any beeps etc?

Check your motherboard and make sure the capacitors are not bludging or are blown?

If every part is checked to be working OK (i.e. tested on another system) then:
-) Is the power switch (2-pin) cable connected to the motherboard ? Make sure it's connected to the right place.
-) Is the reset switch (2-pin) cable connected to the motherboard? Try removing it (meybe it's faulty and keeps resetting).
-) If the computer makes any beeps then you should look at the manual to see what the beep codes mean else check to see if the CPU is sitted firmly in the socket
-) If there is no led lit then check the power supply unit (PSU) and its connections.
-) Are the memory modules sitted firmly? Remove and reinstall them to make sure.
-) Is the heat sink working and/or sitted tight on top of the processor? May be the CPU is overheatting. Make sure!
-) Is the motherboard assembled correctly? Maybe a short circuit somewhere? If everything else fails then remove the motherboard from the case and try re-installing it making sure there are no unneeded screws on the case.

If not sure if every part is OK then:
-) If there is at least one led lit but the fans or the hard disk is not spinning then most probabbly there is a problem with the PSU
-) Remove the VGA and power on. If you get no beep sound then there is maybe a problem with the motherboard or the CPU.

Thanks for the replies guys
 
         But most of the questions are about checking every hardware. I've checked my hard disk
on another pc and it is working fine. I also checked my RAM and its fine with other pc. I also checked my processor and it is also fine.
       
           MBoard is built in with VGA and SOund. I don't know how to check them. I tried to unplug cables and reconnected them with different orders but nothing happned.

     One more thing, PC don't gives any beep when it turns on.
 
                 Can somebody tell me how can I check if any capacitor is blown or not working. Are they repairable.

                      I've tried my best to sort that problem but in vain.
 Plz help

InnocentDevil

If the caps are blown they will be swelling or leaking, yes it is repairable but you need to be able to sloder and desolder.
From the sounds of it your power supply is dead. Try a new power supply.


Eric

last things to test

are power suppply

and motherboard

if when you press the power button , the power supplt turns on then  its a motherboard jumper issue
if its a good board.

if you get no power what so ever , then its dead / or power supply.

get the manul and read throu it.

>MBoard is built in with VGA and SOund. I don't know how to check them. I tried to unplug cables and reconnected them with >different orders but nothing happned.
>One more thing, PC don't gives any beep when it turns on.

Its definitely either your motherboard or power supply.

When you turn on the PC if you get LED power lights, power supply fan spins up (you may or may not get beeps),
but no BIOS post then its your Motherboard.
If its just dead completely, no beeps, no LED's, no power supply fan spinning then its your Power supply.

You need to swap/replace whichever scenario above fits your problem.
Replace and retest.

I JUST had this problem three days ago with a computer. I swapped video cards and the computer worked fine! The problem was with her video card. If your LED's on the motherboard are powering up properly, then it is your video card. See if you can get a second video card and put it in there to test it.

Also, did your computer beep before? If it did when it was working, and it doesn't now, it sounds like a bios chip (or something crucial) gone bad. The first thing I'd do in that situation is simply reset the CMOS with the CMOS jumper (should be near your battery).

A third possibility is your CPU. I had one of these burn out on me too. The way I tested it was to simply put the bad CPU in a motherboard I knew was working. It didn't boot, so I knew the CPU was bad. After I replaced the CPU everything worked fine.

Good luck!

asmodeusnz,


please read other posts before you post a comment I have already suggested what you have said

mckeough,

I beg to differ, just because the LED's on the motherboard light up does not mean it is a video card problem.  Not to mention we're talking onboard video here.   In which case it is possible the onboard video may be bad, but doubtful.  and usually in most cases if the vidcard is bad, the system generally gives a beepcode.  

so I would have to agree with the general population that it is either the Power supply or the Motherboard...  However I really think it is the Motherboard and not the Power supply.

Also realize that even tho the memory may work in another machine, does not necessarily mean they are good.  There may be defective spots on the ram that may cause it to not post in one machine but to post in another...and believe me...I've seen it.  probably about 7 or 8 times last year in customer's machines.

Thanks guys once again
            After reading all of your comments I once again checked all the things. For the Power Supply, its ok 'cuz when I turn on the PC everything starts up like fans, lights etc. I'd this problem before but it was fixed after I replaced RAMs correctly but this time I don't know.

        I think my power supply is ok and there is MBOARD problem or BIOS problem or it may a capacitor problem 'cuz I smell like something being burnt.

            What if capacitors are burnt. Can I show them to some hardware engineer to fix them up or they are not repairable ???
 
 Thanks
 
 InnocentDevil

As stated earlier, they are repairable, but that requires soldering new ones onto the board.  Parts like that are not easily accessible locally, cept thru maybe an electronics shop or something.  
Here's a look at how to tell if caps are bad:
http://www.badcaps.net/ident/
http://home.earthlink.net/~doniteli/index27.htm

Lastly the only way to trully rule out bad components is by using a multimeter and testing the Ohms, Voltage etc... and making sure they all match to specifications. So you will have to spend hours poking and prodding all the components on the board including possibly the capacitors

I agree with Brian. He made an excellant case for replacing the motherboard. I've lost cound of how many computers I've built, but when something like a motherboard goes bad on one of them, the cheapest, quickest, and all-around most economical way to do things is to replace the whole unit. I use www.pricewatch.com. Go there and look up prices for motherboards.

I used pricewatch to find this one: http://www.computerbrain.com/cbisys/buy.asp?main=Motherboards&title=ASUS&id=118

Don't let the price fool you. If you go to www.tomshardware.com and look up Asus, you'll find that this motherboard is one of the best on the market. That's just an example though. If you're running a pentium, you'll want a different version. Once again, good luck!

Here's a Pentium version:

http://www.partspc.com/store/product3554.html

innocentdevil,


just wondering why a grade C ????

maybe it was because your comment was too long!   :)

j/k

Im sorry to say, But your BIOS is gone. A lot of new computers, Particularily IBM have a "Secondary BIOS" that you can use if you screw up the first one. By the sounds of it, you dont have one. Did you try to flash the BIOS? if so people who dont have  A LOT of experience doing this really should have a pro do this. When you lose a BIOS, And don have a secondary BIOS, YOu have to get a new MB.

Hope this helps,

rpatno

It may not be the bios.  Just cuz he gets no display, does not mean the bios is bad.  And sometimes you can replace the bios chip (which can be cheaper than buying a new board.)  Most manufacturers will provide a bios chip for $20.00.  Plus shipping.  Some misflashed or  bad bios' will at least post.  And you can see an error message usually telling you that the bios has been corrupt etc.  I've seen a few of these in my day.  But when a system doesn't post....it may be a faulty component on the board....sometimes it CAN be the bios...but not always.   But if the asker wants to save some money, and TRY to get a new bios chip, if indeed the bios is bad....then by all means...but that may not solve the problem if something else is faulty on the motherboard.