Why laptop making beeping noise?

You might want to check on HERE for the beep codes of your dell. I would remove the AC power, remove the Battery and also the RAM. Then try to reinstall it with only on memory module at a time. Also try one module in the different slots and see f it makes a difference. If your computer beeps 7 times, it is possible that it is actually a 3-3-1 beep which points toward the memory. Good Luck and let us know so we can all learn.

Depending on the beeps you should check the Memory or the Battery. Try connecting the power and then remove the battery so it boots if you still get the beeps you might have change your memory.

just clean memory and try 4 times if dosent work maybe you need to replace your ram.