Mute "System Speaker" in the mixer, or make sure that the sound settings are "default" in windows, i've seen some 830s do that when there is no alert sound to play, so the BIOS sends the beep.

So I bought Dell Inspiron M5030 for my daughter last spring, second hand off ebay and we've been quite happy with it. Last night I was borrowing it and was d/l a big file, running a defender scan, ...