The beeping sound can be an indication that there's a loose connection inside the laptop. Here are some troubleshooting steps that may help.
- Start by doing a hard reboot, remove the battery and unplug the AC adapter then press and old the power button for 20 seconds then try booting it up again.
- If this will not work proceed with reseating the RAM's, remove them all for couple of seconds then place them back in making sure everything is seated properly.
- If you'll still get the beeping sound you'll need to open the laptop and make sure that the ribbon cables that connects the LCD to the motherboard is seated properly together with the Touchpad and Keyboard.
Thanks Lot for your valuable answer. There was a loose connection with the ribbon cables. i open the laptop and reseated the connector properly. It work. the laptop is working fine. Thanks a lot again. God bless U.