Computer problem When I press my computer power on button computer goes into unstable state..There will be no display on screen( Blank screen). I have to remove power cable to shut it down. Please provide me the solution.

There's a number of possible problems. A momentary press of the power button will probably not turn the computer off, in this state, but holding it for 4+ seconds usually will. Did the computer work previously? If so, did something change recently? Usually, this sort of problem will arise after a hardware change; e.g. installing more RAM, changing something in the BIOS settings, installing a new video card, etc. If nothing changed (including things you may not have been aware of), and the computer just stopped working, then a part may have failed, possibly due to a power surge or similar. Depending on your computer knowledge, comfort with working on your computer, and whether there's any warranty in effect, would determine any additional action. Please provide additional details.