Hi vinidhi
sorry to hear you are having this issue, is the laptop still under warranty?
Things you can try;
1: Remove the power lead and battery and hold down the power button for 30 seconds, replace the battery and try to boot up, if no luck;
2: Remove the battery, attach the AC power adapter, attempt to boot up, if no luck;
3: Remove the Ram, hold down the power button for 30 seconds, attach the power, attempt to boot up (it will not without the Ram)if the laptop does switch on power down and insert 1 stick of Ram (if you have 2) and attempt to boot up.
Let us know how the above tests work out, it depends on the test results what advice someone will give you next.