According to my "Beep-List" it could be a problem with  the "Real Time Clock" (a clock modul located on the mainboard and powered by a Coin-Cell battery)

possible solutions:

> remove (main) battery and power adapter - press the power button for a couple of seconds - reconnect the power adapter and test the system

> press F2 at powerup and reset the BIOS to default settings

> replace the Coin-Cell battery see link below

   http://support.euro.dell.com/support/edocs/systems/insN5110/en/sm/pdf/om_en.pdf

> if your system is still under warranty you may want to call Tech Support before replacing the Coin_cell Battery

Hi,

Beeps are diagnostic indicators on a computer that generally indicate that there is an issue with the hardware of the computer.

In this scenario you have 5 beeps on the computer. Generally 5 beeps means that issue can be related to Real Time Clock which is caused by Coin-Cell battery which is located on motherboard.

If you are comfortable in replacing the coin- cell battery, try to replace the coin cell battery, providing the manual link for reference:http://support.dell.com/support/edocs/systems/insN5110/en/sm/index.htm

If not I request you to private message the system service tag number. To private message, accept my friend request; click on my user name and click start conversation.

Alternatively, you can check warranty status online. Click on the link below: 

http://www.dell.com/support/troubleshooting/us/en/19/TroubleShooting/ProductSelector