Here are some troubleshooting steps that may help in solving the issue.
- Start by doing a hard reboot, remove the battery and unplug the AC adapter then press and hold the power button for 20 seconds then try booting it up again.
- If it will not work reseat the RAM's, remove them all for couple of seconds then put them back in making sure everything is seated properly.
- If it will still beep try powering on the laptop without it's battery and just connected with its charger.
- Do also make sure that there are no other devices are connected.