The beeping sound could be an indication of a hardware failure or sometimes just a loose RAM.
- Do a hard reset first, remove the battery and AC adapter then press and hold the power button for 20 seconds. Plug just the AC adapter and see if the laptop will boot up normally and if it does you can put the battery in as well.
- Reseat the RAM, take them all off for couple of seconds then put them back in making sure that they are all seated properly into each slot.
- Lastly is to try and remove the HDD and see if it will boot up with it.
- If all these troubleshooting steps will not work, do contact Lenovo support for a repair if it's still under the factory warranty.