my computer turns on for a sec then just clicks off. will not start up at all.

Well, they're not really supposed to do that in all honesty.

Is it under warranty?

Is it a laptop or desktop? How old? (or rough idea of specifications)

If a desktop, is it a Shuttle PC? (or in a small case?)

When you say "a sec" is that literal or does anything appear on the screen?

Have you made any changes to your computer in the last few weeks, added any new hardware or had the 'lid' off for any reason recently?

If not, had your computer started doing anything peculiar leading up to this? (abnormally resetting itself, or reporting unusual errors, etc...)

no it hasnt its homemade but it has not done anything weird its a desktop and its so fast that nothing appears on the screen.

Sorry for all the questions... when you say home-made, is this a newly put together system?

If you didn't build this PC then get the person who did to have another look at it.

If it is a newly built PC, make sure you have connected the processor fan, and then double-check all of your connections to the motherboard.

Do you know what motherboard it has? For example, is it an "Asus P4V800D-X"? Once you can tell me this I'll download the manual and offer more suggestions. Keep your manual handy too.

If it is not a newly built PC, and you haven't made changes recently, then something inside has died. It could be your Power Supply Unit (PSU), your CPU Fan, your CPU, or a few more things. We'll help you narrow it down... but it will mean a few more questions if that is okay?

it is not newly built its close to a year old. i built it i thought it might be the PSU but i wasnt sure so i thought i would ask

Coincidently, I have recovered from a similar problem. Let me describe what happened to me.

About 2 weeks ago, my computer shut down unexpectedly. When I tried starting it again, nothing happened. I switched the plug point power supply on and off and managed to get the PC started again.

Now, this problem progressed (more random shut downs, and they started happening more frequently) over the next few days. I would go for days with no problems and then - bam - it happened again, and again.

I suspected hardware, just like you. Until I noticed that the ADSL modem was also resetting itself every time these random shut-downs happen. Both, the PC and ADSL modem share the same plug-point.

Immediately I used a different plug point for my PC and everything ran smoothly. However, my modem kept disconnecting from Internet now! So, I found the culprit... it was my 'new' plug point, the one I got someone to put up, a couple of years ago.

The electrician said that it was a faulty MCB, I think that means: Miniature Circuit Breaker. He replaced it for RM5.00! (less than $2.00)

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