Computer startup issues?

The most possible cause is your PSU ( Power Supply Unit ) is defect.

Stop trying to power on the computer or you're on the risk of damaging your harddrive and possible other components too.

Replace or repair the PSU, if possible borrow one from a friend which compatible with your CPU.

ADD:

Ohh...heck

Well, if it's all in one, I think you should contact nearby Dell customer service because I think it's hardware related and you might be in the risk of losing your product warranty if you try to fix it ( blindly ) yourself

here is what should happen under NORMAL operation

for good quality equipment like DELL.

A PC power supply must be kept PLUGGED IN at the wall

socket with the wall socket ON. This keeps the PS in standby.

During this time it POWERS the MOBO.

whilst the MOBO is POWERED it is in STANDBY. During this

time it MONITORS the state of the ON OFF button which is

SENSED and does NOT act like a SWITCH. It just gives an indication

that you would like the POWER SUPPLY to START the MOBO.

to do this succesfully and avoid a FAILED start the power supply

and mobo must be charged up if you like, ie plugged in, in standby

for more than 30 secs.

Thus if you walk up to the socket on the wall, turn on the power,

then immediately press the ON switch on the pc. The pc and supply

will NOT be READY yet. You MAY get a start but like as not you

will get one of these

1 the computer may try and kick in then give up within 5 secs

2 it will appear to start, hard drive kicks in, monitor on, but graphics card

...fails to start. pc will just sit there till you turn it off

3 you may get a kind of start thats a bit wobbly, and by the time your

...log in screen gets up anything could be happening including not actually

...managing to get any further.

4 sometimes on switching on the wall socket the pc may false start. Turn it

...off immediately as it wont be a reliable start. wait the 45secs or so before

...switching on properly

There is one more spanner in the works.

Dell supplies and mobos have intelligence in them. For a CPU

when it first gets its hit of power, it pumps out a massive heat

surge. This is compensated for by the FAN doing a quick burst.

Im sure you know what i mean.

If you restart the mobo, more than a certain number of times,

in a few minutes, then a FAILSAFE MODE kicks in. This is

doing you a BIG FAVOUR, it is SAVING YOUR CPU.

The mobo will implement a HARDWARE LOCK OUT by using

a timed circuit to PREVENT FURTHER STARTS. This

lasts for around 30mins. During that time it is FUTILE and

extremely STUPID to try and restart the PC. any success

would permanently damage the CPU and the MOBO.

to re-cap then

1 make sure your power lead is properly pushed into the power supply

...ALL THE WAY IN.(it must fit properly) push it in and out a few

...times to make sure. Make certain it is the RIGHT lead for the PC

...and not a replacement or the monitor lead which may be slightly

...different as regards the 3 sockets and how well they make contact.

2 Make sure your wall socket is in GOOD condition. No corrosion

...that is indicated by sparking plugs. Replace if more than 10 years old

3 make sure the PLUG is in GOOD condition, no corrosion to

...cause sparking plug. Replace if in doubt.

4 Leave the wall socket ON to keep the mobo in standby.

5 if you do need to turn off the wall socket, then wait 45secs after switching

...it on, before you push the pc start button to allowing charging up

...and settle down time. If the pc auto starts when you switch the wall socket

...on, then just hold the pc start button in for 5 secs to force it off until the 45secs

...has passed.

6 NEVER restart the pc multiple times in QUICK succession.

i hope this helps you understand why your pc is doing what it is doing

a power supply holds enough CHARGE to KILL you.

messing around with sparking circuits is very stupid thing to do.

That's the drawback of convenience. Your PSU is most likely faulty. You should take it to a professional if you are concerned about damaging the unit yourself.

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