The last day my computer worked perfectly.
On the next day wen i turned it on , the cpu is in on condition,but there is nothing displayed.

So i've removed all the power cables and RAM and also the processor. and put it back as it is...

But the problem continues...
Now, wen i press the power button the CPU turns on a while and it turns off within 15 sec...
I don't hear any of the beep sounds...
Then i've resetted the cmos too..
But the problem continues...

Tell me a solution for these..

It would help if you told us what computer it is!

Did you check the fan's?
Did you try putting only one stick of RAM?
Does the Power Supply spin ?

Did you put Thermal grease on the Heatsink when you put CPU back?

We need more informatio like what is your computer model. How old is your computer? And what is your OS? When you start up your computer, you said you see completely nothing.

1) Is there any words like monitor going to display or others?
2) Are you sure your conputer is fully charge and is the power cord plug in properly. Take out the cover and check the parts to see whether any of them is not place properly or faulty and old parts. Did you remember the last time you did a scan, whether there was a virus on your laptop. If yes your antivirus software might not have remove the virus completely and it is still in your hard disk. It may be damaging it that is why this problem occur.

Your problem might be hardware related or a virus infection.

Getting no display means there is problem with your GPU or with your monitor. To check out what is causing the problem, make sure GPU is properly inserted. You may try removing and reinserting it. Next you can also try your GPU with another computer to make sure it is working. Also try connecting another monitor to this computer to make sure your monitor is not at all faulty.

Its config is Intel pentium 4 processor
mercury motherboard
Monitor is working properly..thr is no display in monitor...
Monitor led on & off repeatedly...
I've removed & inserted all the parts..
But i did't get my computer started.

Have you try our suggestion?

Just yesterday had to fix (by replacing the motherboard) a very similarly manifested problem whereby the PC would turn on, display dark, HDD revs up but then spins down. No diagnostic beeps. CPU fan would spin continuously (older PC, probably not even setup to turn it off).

The issue was (I surmise) the northbridge chip damaged by overheating. The little fan on top of it got completely jammed by dust and has not been working for a while, so I think it just finally got burned.

Sorry to say that but it was not a cheap or a quick repair - when mobo goes, to replace it, it's more work than putting together a brand new PC. An the mobo is the most expensive piece, save the processor.

Good luck!

FROM my little experience, its not monitor problem but power supply problem or RAM problem. But power supply problem very high. Yes ur computer can turn on for sure without any display. Because of power supply problem im already dumb alot computer. But at last im manage to figure it out that just minor problem and it is your POWER SUPPLY

I had the same issue. I just reset the power supply by turning on then off using the switch on the power supply