Is the beeping evident when plugged in, when running on battery power, or both? Is the beep related to anything in particular that you can ascertain such as a dead battery or a key being stuck on the keyboard?
Are you receiving any error messages or prompts during boot up to give you insight as to the source of the beep?
If the beep is battery related, I would at least try running the machine from the AC cord without the battery installed. Conversely, depending on your particulars of your laptop, with which I'm not familiar, a loose or flakey connection to AC power could actually be causing the laptop to switch between AC power and battery, causing a beep each time.