Rame,

   Your computer has power connection issue. I am telling you I had exactly the same issue.. I bought new laptop but later i fixed the old one as well..

Your laptop works sometimes, the disconnectivity is connected in power path inside somehow...and it works.. Computer is not getting power due to some of these issues -

1. Main power adapter itself is not working/ loose connection... Try with friend's power adapter of same brand if available.

2. The power plug connection inside the computer is not working. . Open the laptop (go online search for instruction).. Some wire for power supply must have been unplugged.. Look for that..

If you were nearby me, I would like to give a look to your laptop.. and of course win the bumper prize ;)..

It is not big issue..