Computer does not start anymore

AMD motherboards won't start if the cpu fan is not connected to the cpu fan header.  You may have knocked a wire loose somewhere while you were cleaning, or unseated a card.  If you used a regular vacuum cleaner, you may have introduced static electricity.

Try it with a minimal system.  Include one stick of RAM, the cpu, and the video card, and reset the BIOS.  Do not include hard disks, other PCI cards, or other peripherals.  If it works, add more components; if it doesn't, you will have to swap the parts in there until you identify the bad one.

I checked the CPU fan and everything looks alright. I tried to start the system, only with the CPU and the RAM.

How do I determine if the problem is the power supply or the mainboard itself?

Power supplies can be tested with a voltmeter: http://www.extremeoverclocking.com/articles/guides/Power_Supply_Guide_1.html

You can also buy a dedicated tester: http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=561263

Testing the motherboard is very difficult.  If it doesn't have obvious damage, like bad capacitors (www.badcaps.net), leave it as the last resort for replacing.

Are you getting any beeps?

When you plug in the power supply, generally you hear a high pitched noise.  if its working.  I would also recommend taking the cmos battery and trying to power it and then putting it back in once the power is off.  
If you aren't getting any mobo lights, my guy instinct says that you may have some antistatic discharge or loose capacitors.  Pretty unlikely that the psu has gone down.

are you sure its not a FUSE on your power cable?

Since your power led on the motherboard does not illuminate with either the old PS or the new one Your attention should be focus on the PS.
Is AC power available?
This is a bit wild but always eliminate what you can. A new PS comes with an AC power supply cord did you try the old one and the new one. Then verify power at the source (outlet).
Check the power scitch cable it should be a small green and whit cable. Ensure it is attached to the right set of pins . While you are there check all of the connections in that area.

These connections are located at the lower right coner of your board.
Also reseat your CPU. If the CPU has worked itself loose, the mainboard will shut off power to the board. Sort of self protection..

Hay Chris I had a similar problem It happened due to ram not being seated properly try takeing it out and reseating it that may help if you havent tryed that allready

Hi. I tried following:

I reseated the CPU and the RAM. The power supply does indeed some noise when connected to power, but that's about it. I tried 2 different power plug cables. I checked all connectors, everything looks normal. I don't have a voltmeter to check the power supply, but it is brand new, so it actually should be ok. In case of an antistatic discharge on the mainboard, what is there to be done? Or maybe you have other ideas...

When you hit the go button, does ANYTHING happen?  Lights on keyboard flash, fans run (or even try to start turning), any sounds (beeps, etc.)  If NOTHING is happening, then it could be power supply, mobo, or switch.
You can eliminate the switch and the little switch cables by using a small flat blade screwdriver to short the pins that the power switch connects to.  It's not an exact science, so you may have to play around with it to get it to take, but you just touch the blade across the "PW" pins on the jumper bank (it may be labeled J2).  I think the pins represented by X's below are the ones:
 ------------------------
| O O O O O O O O O |
| O O O O O X X     O |
 -------------------------
If STILL nothing, take out the video card and RAM, and try with just mobo and cpu to see if you can get any sound, fans, etc.  If you get no action with just power supply, mobo, and cpu, one or more of those 3 is bad.  (I say one OR MORE, because maybe your new power supply had a problem and when you plugged it into your old motherboard, both became junk).
I hope it's just a loose wire on the switch or something as easily fixed, but I'd be afraid to speculate.
Best of luck!
jb

I added a few images, maybe it helps:

http://img.photobucket.com/albums/v490/images2k5/bscap001.jpg
http://img.photobucket.com/albums/v490/images2k5/bscap002.jpg
http://img.photobucket.com/albums/v490/images2k5/bscap003.jpg
http://img.photobucket.com/albums/v490/images2k5/bscap004.jpg
http://img.photobucket.com/albums/v490/images2k5/bscap005.jpg
http://img.photobucket.com/albums/v490/images2k5/bscap006.jpg
http://img.photobucket.com/albums/v490/images2k5/bscap007.jpg
http://img.photobucket.com/albums/v490/images2k5/bscap008.jpg
http://img.photobucket.com/albums/v490/images2k5/bscap009.jpg
http://img.photobucket.com/albums/v490/images2k5/bscap010.jpg
http://img.photobucket.com/albums/v490/images2k5/bscap011.jpg

Nothing happens when I hit the "go" button, no flashes no beeps, no sounds of any kind, just plain silence. The video card was taken out, from the beginning...

NEWS!!!

IT just started!!! But the CPU fan is moving pretty slowly...or maybe it is just me. Anyway, the green light is on and mainboard started beeping. I guess because there is no videocard installed. What do you think about the fan?

If you had an antistatic discharge your mobo is pretty much gone.  From the looks of the age of the computer, I would really think about spending on new cpu as well.  and getting new memory.  Your hardisk and power should be ok for the new cpu and mobo.  

" I would really think about spending on new cpu as well". Well, this is my linux server and I don't want to invest money in it, it does fine for its purpose. My workstation has, of course, other hardware in it. I will insert the video card now and do further tests.

Replace your fan, if it is moving slowly - a non-working cpu fan has the same effect as an unplugged one.  As far as the system is concerned, if it doesn't detect a working fan, it doesn't boot.

You could have a bearing siezing or a bad bushing in the fan. Try spinning the fan manually to check if it speeds up. You may have turned it while reseating the CPU  

The fan moves now, but there still is a MAJOR problem. The system powers up, every fan revolves, the CPU fan, the VGA fan, the power supply fan, but then, I don't get the usual 2 beeps and I can't get no output on my monitor. What is there to do?

Check your capacitors. Callandor gave a reallly good site earlier www.badcaps.net
run run finger across the top of the caps next to the CPU, they should be flat. If you feel a bulge tell your MB goodnight unless you want to try your hand a soldering. The same goes fo a visual of the lower portion, if they are bent of bulging, solder or toss it.

Early AMD boards were notorious for this problem. Why did you replace the PS if the old one was still working? More curiosity than anything else. I know PSs are supposed to regulate the power but I wonder if the older MB are expecting to regulate 100 - 250W and then get zapped with 400 - 600W. Just a thought

Because, the old PS started smelling like burned, it still worked, but I didn't want to risk anything. The capacitators look ok, just checked them. What else can be the problem?

If i set the CMOS on CLEAR, it will clear my CMOS and I will have to change my CMOS?

If you now have the new power supply in, check for a switch on the back to set the voltage (110 / 220).  If you have 110 power, but the switch is set to 220, you will get lights and maybe some fan action, but no post.
jb

I have 230 V and the power supply is set properly.

Hi!

I took out the CMOS battery, but nothing has changed.

How can I determine if the mainboard or the CPU is the problem?
What causes the 2 beeps when the system starts normally?

Something odd:

Sometimes when I start the system, the cooler of the VGA card does not start. If I shut it down and restart, then the coolers spins normally. Also, sometimes, the cooler of the CPU makes strange noises, but after i shut it down and restart it, everything is fine. Isn't it odd?

Looks like the Power SUpply is the culprit. Its either giving extra volatage or under voltage which are causing this problem. My suggestion wud be to stop using it ASAP before something else gets damamged and have it replaced preferably with an older model power supply.

The twin beeps indicate health status for the board in some cases and the reason ur not gettin them is that the voltage or some other sensor on the board is not sending the ALL OK to the BIOS and hence no beeps to indicate all is well.

Dan

Yes, the need to repeatedly startup sounds like the power supply is bad.

You can only determine if the cpu is bad by trying it out in another system that you know works.  If the cpu is good, then by process of elimination you conclude that the motherboard is bad.  The motherboard is too complex to test and conclusively know that it is good or bad, apart from installing it and trying to use it.

Hello!

Today I connected a new power supply on the system, but the system behaviour is the same:

LED on the mainboard lights up, fan of the power and CPU start spining, the fan of the graphics card does NOT.

I took the graphics card out of the AGP slot and reseated it. The fan works now. But 10 seconds after the start, the CPU fan starts to make strange noises and revolves at a slower speed until it stops. But if only that would be the problem, then the system would boot in 10 seconds when CPU fan works alright. Isn't this true?

I thought you had replaced your cpu fan?

"Replace your fan, if it is moving slowly - a non-working cpu fan has
the same effect as an unplugged one.  As far as the system is concerned,
if it doesn't detect a working fan, it doesn't boot."

I didn't do it yet (will do it next week). But my concern is that it actually revolves in normal parameter for a certain period of time, so why would the mainboard halt all activities?

If the fan stops, the motherboard will stop.  It's not clear from your posts what is happening when.

The behaviour of the mainboard before and after the fan stops doesn't seem to change...

Maybe you should put the dust back into the case? :)

Hehe, that's not funny, no offense.

Looks like the New PSU u put in or the older one u pulled out damaged something on th board. I hope the power supply ur putting is an older model one and not the newer 400 WATT models which sometimes tend to have different ATX compliances and cud be the one triggering of the problem on ur board.

You have already tried this with ur Older PSU with the same result which leads to the fact that something has been broken in the board while cleaning or pulling and reinserting the cards.

Try and take out the board from the cabinet and put it on a piece of cardboard and then plug in the CPU+RAM+Graphics card and then try to start the system up. The reason that the fan starts normally is that the break in circuitary increases as the components get heated up after a few moments. I have seen this happen on occasions and not much u can do abt it. You can try and take out the mainboard and give it a few gentle taps just in case its a dry solder for one of the chips/capacitors and hopefully that might make it ok. Check the board for anything loose that u might find out of the ordinary. It might be time to get a new board else.

Dan

Hello!

I changed the RAM from the Slot3 to the Slot1 and now, the system boots, isn't it odd?
I am glad the motherboard is ok.
Thank you!

That is odd - perhaps you had a defective RAM slot, which can happen.

perhaps soem dust settled into the slot preventing full contact with the RAM and the second slot didnt have this problem.

Cheers on getting it sorted out.

Dan