I faced a similar problem.
First, do u get a small beep sound when u switch on ur system?
If no, then ur battery is not working. Replace it.
If yes, then ur RAM is loose. Remove it and replace it and ensure its not loose.
This worked for me. Hope it works for you too.
Goodluck.
karlabaw :
i have a thin blue line appeared in my monitor and when i removed it from its connection to the video card (for cleaning reaso