Power supply sometimes turns off

Actually its not the matter with the Power Supply,but with the CPU Cabinet Power Button.I recommend that you should replace the Cabinet.It will surely help,and for the freezing problem it's your Hard Drive problem,you can also try re installing Windows...!!
But for the Power Button problem you should definitely replace the cabinet

Hi,

This is a typical symptom of a failing power supply. Replace your power supply and see if the problem still persists.

Please notify me should you need any further assistance.

Best wishes,
Graemevm

I would check the power options and set them to never power off at any time. You can find this in the control panel. Also if they are all off I would consider replacing the power supply unit. Sounds to me like it shows signs of going out this is what the do and eventually they just go out and that is it computer will not come back on. Power supply unit. John

Try these simple steps that I have below:

1. Believe it or not, the number one reason why a computer won't turn on is because it wasn't turned on!
2. Before starting a sometimes time consuming troubleshooting process, make sure you've turned on every power switch and power button on your computer:
   
3. Verify that the power supply voltage switch is set correctly. If the input voltage for the power supply does not match the correct setting for your country, your computer may not power on at all.
   
4. Check for disconnected computer power cable connections. A loose or unplugged power cable is one of the top reasons why a computer doesn't turn on.
   
5. Perform a "lamp test" to verify power is being provided from the wall. Your computer isn't going to turn on if it's not getting power so you need to make sure that the power source is working properly.
   
6. Test your power supply. At this point in your troubleshooting, it's very likely that the power supply unit in your computer is no longer working and should be replaced. You should however test it just to be sure. There's no reason to replace a working piece of hardware when testing it is fairly easy.
   

1. Believe it or not, the number one reason why a computer won't turn on is because it wasn't turned on!
   Before starting a sometimes time consuming troubleshooting process, make sure you've turned on every power switch and power button on your computer:
   
   • Power button/switch on the front of the computer
   • Power switch on the back of the computer
   • Power switch on the power strip, surge protector, or UPS (if you have one)
2. Verify that the power supply voltage switch is set correctly. If the input voltage for the power supply does not match the correct setting for your country, your computer may not power on at all.
   
3. Check for disconnected computer power cable connections. A loose or unplugged power cable is one of the top reasons why a computer doesn't turn on.
   
4. Perform a "lamp test" to verify power is being provided from the wall. Your computer isn't going to turn on if it's not getting power so you need to make sure that the power source is working properly.
   Note: If you have a multimeter or another electrical testing device you are welcome to use that to test your wall outlet (and power strip, surge protector, etc.). The lamp test is useful if you don't have an electrical testing device.
   
5. Test your power supply. At this point in your troubleshooting, it's very likely that the power supply unit in your computer is no longer working and should be replaced. You should however test it just to be sure. There's no reason to replace a working piece of hardware when testing it is fairly easy.
   Replace your power supply if it fails your testing.
   Important: In the huge majority of cases when a computer isn't receiving power, a nonworking power supply is to blame. I bring this up again to help stress that this troubleshooting step should not be skipped. The next few causes to consider aren't very common.
   
6. Test the power button on the front of your computer's case. It's not a very common point of failure but your computer might not be receiving power because the power button on the front of your PC is damaged and is not actually turning your computer on.
   Replace the power button if it fails your testing.
   
7. Replace your motherboard. If you're confident that your wall power, power supply, and power button are working, it's likely that there is a problem with your PC's motherboard and it should be replaced.
   

I fully agree with you.

Capacitors have gone bad in the power supply. This causes a weak power rail.

Enough power to spin fans, and light- lights, but not enough power to turn on the Processor. (Harddrive is inactive because there is no processor running)

Power supply's are rated in Watts. (Volts x Amperes = Watts)

1.ALL the lights use less than 1 Watt.
2.EACH fan uses 2 to 3 Watts.

A typical Processor uses 55 to 125 Watts!
Depends on the processor.

BIOS won't turn the processor on, and hand the computer over to the Operating System, (Example: Windows XP), because there isn't enough power.

CAUTION!!

I DO NOT advise opening a personal computer power supply!
Those Electrolytic Capacitors I have referred to, hold a charge for WEEKS, sometimes MONTHS, after the power is disconnected to the power supply.

Capacitors are made to slowly build up a charge, then release it all at once!

If someone touches across the terminals of a capacitor, and it's still good, it can release it's charge to them!
If someone touches a circuit that capacitor/s are in, the charge can be released to them!

Shock can range from BAD to FATAL!

It is for this reason that the best, and most effective method, is to replace the power supply with a known, good one for a test.

I realize power supply's do not grow on trees, and not everyone is a computer geek like me, and has several laying around, (I mean Tech, lol!)

IF you are stating this question referring to an eMachines that uses a Bestec ATX style, 300 Watt power supply, the cost is very inexpensive for a new one.

Not to slam a company, but Bestec PSU's are cheaply built, and this is the reason it failed. (IF yours is a Bestec)

You don't have to break the bank however, to replace this power supply with one that is much better.

An ATX style of power supply is a very common one. Approximately 85 to 90 percent of personal computers use this style of power supply.

This example would get you buy for quite sometime, (IF you keep the inside of the computer clean regularly, and the power supply, with a can of compressed air for computers. 75 percent of failed computers that come to my shop are dirty inside)

http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=719582&CatId=1078

Just an example. Not advertising for the power supply manufacturer, not the website.

Have any additional questions I'm right here.

there are many reasons behind this are as follows :-

• inproper power supply
• due to bad earthing
• may b the chances of system crash
• due to viruses

these are some reasons so checkout those things.
also check the monitor & mouse setting from control panel.

what size power supply are you using, if its under 400 watts it may just be under powered. Large video cards 512mb and over take a lot of power. Try removing the video card and see if you can get the pc to power up, hopefully you have on board video.

How did you blow the cpu_fan connector, did you short it out? I would first supect the power supply is under rated, second a blown power supply, or mother board.

1.check power supply section any dry points
2. To replace all electrolatic capacitors in Power supply
3.Check Connectors Properly connected Or Not.
4.Replaced Microswitches in Front pannle.