Laptop keeps beeping.

I own a old Gateway NV52 and everytime I turn it on it beeps for like 5 minutes and then stop. The battery symbol with the plug keep flashing and sometime make my screen flashes too. At first I thought it was the battery but I replaced it even taking it out it still beep, could it be the AC cable? I also did a clean installation.
Answer #1
Google….Gateway NV52 beeps…. It sounds like it might be normal..
http://forum.notebookreview.com/gateway-emachines/418542-gateway-nv-power-cord-beeps.html
It seems that muting the speaker should stop it, a bad design fault!
Answer #2
I tried googling it but I have yet found a answer. The weird thing is http://images.mobilityminded.com/2009/08/win7_action_center_588px.jpg (not my screen) the battery icon on the bottom right with the plug, the plug would go on and off while beeping, maybe the laptop outlet is faulty? But then again that laptop has been plugged in like 95% of the time since its always been connected to my TV.