The 7 beep code indicates that there is a processor/motherboard failure. Try releasing the static power and check the system is working. Follow the steps below.
Switch off the system; remove the battery, ac adapter and the power cable. Press and hold down the power button for thirty seconds to drain any excess static power.
Let me know about the progress.
I have no idea about the removal of AC adapter, Can you please guide me how to remove AC adapter?
In case if it is not working then also guide me how to submit laptop for repair?
Unplug the AC adapter from the system, remove the battery and hold the power button for 30 seconds.
If that doesn't solve the problem, a mainboard replacement will be required - if the system is out of warranty, that will cost about $200-300 just for the board; add another $100-150 in labor if you don't change it yourself and the repair becomes questionable from a cost/value standpoint vs. replacing the system.