Dell Inspiron n5010: Working fine, but beeping constantly

My Dell Inspiron n5010 (Windows 7 Ultimate, 64bit) recently recovered from an LCD problem (8 Beeps), that I managed to fix with an external monitor, 'Startup Repair' and new GPU and BIOS drivers that were recommended by the Dell 'AutoDetect' feature on the website.

The laptop now works fine (as far as I know), however, it constantly beeps, then pauses, then beeps some more.

Note that this problem does not persist if I booted the laptop as it was connected to an external monitor. As long as I booted it connected to one, it won't trouble me.

Is there a fix for this problem, as having to rely on an external monitor for a laptop kind of destroys the purpose of portability. The battery is pretty old and I can't just put the computer to sleep to move it somewhere else without it shutting down itself.

I have not tested if the problem persists if it boots from a hibernation.

Thank you,

Chayse.