computer shuts down after it turns on

[dr.r0ckz0]

hello, my problem is that my computer turns off when i turn it on. sometimes it does not even go to the startup screen. my monitor says it is going to sleep after maybe 2 seconds after the computer turns on and then shuts down. my computer is an hp m8400f, with an AMD Phenom 9500 Quad-Core Processor, 3072MB system memory, 720GB hard drive, Nvidia GeForce 8500GT graphics card, and Windows Vista.

[hot dog]

Do you have a power supply of equal or greater wattage that you can borrow from another computer, or someone?  Try to borrow one and swap in in there to see if that's the problem... If it works, give the power supply back to whoever you borrowed it from and order another one..


Have you changed anything inside the computer lately, like unplugged cables or made any other physical configuration changes?

Have you looked inside the computer lately, period?       There may be a serious dust factor..In which case you need to purchase a can of compressed air and thorough clean out the inside...

[Karnac]

my monitor says it is going to sleep

What is the exact message you get ?

[dr.r0ckz0]

i havent looked inside since i know nothing of the inside of a computer, but ill see. for the power supply, i switched it with my monitor's cable and same thing. my monitor just says 'monitor is going to sleep'

[hot dog]

i havent looked inside since i know nothing of the inside of a computer, but ill see. for the power supply, i switched it with my monitor's cable and same thing. my monitor just says 'monitor is going to sleep'

When I say power supply I don't mean the cable..... I'm talking about the large cube-like thing inside your computer that the cable attaches to.  The power chord plugs directly into it.

It's fairly simple to pull out and replace.....But you have to make absolutely sure that every connection the current power supply makes to the motherboard and peripheral components, is replaced by the power supply that you borrow...Take a long close look at what the current power supply is attached to, and duplicate those connections with the power supply that you borrow........

You must also make sure that when you do replace the power supply that it is unplugged from the wall.   Static electricity is also a factor to be concerned about when opening a computer.....  After unplugging the computer and opening it up....find some unpainted piece of metal and touch it a few times to discharge and static electricity that may be lingering....  And if you move around a little, more static electricity could be generated, so touch the non painted metal every few minutes or so..   

Now open the computer, disconnect all connections from the power supply to the computer...find a Philips screwdriver and unscrew the four screws in back of the power supply on the outside of the case (near where the cable plugs into the computer)...be care not to lets the power supply drop down onto your mother board after unscrewing it.....hold one of your hands on it on the power supply...  When you got the last screw out....CAREFULLY pull out the powersupply and put the other power supply in...     Note: you don't have to completely install the other power supply at this point... You can leave it on the table top after plugging it into the computer and plugging it into the wall......  This is only for testing-purposes...  Once you've got it hooked up.....fire it up and see if the problem is corrected..

[dr.r0ckz0]

ok i will try that tomorrow 

[hot dog]

and while you're inside the computer....have a look at the dust factor............look closely at the cpu heatsink and generally, the whole inside 

we don't want any dust build up

[dr.r0ckz0]

it was not my supply unit, but i did find the problem. i asked my cousin for help and he thinks its either my ram or my motherboard. so im going to use my warranty to fix this issue, but thanks for the help