Internal speaker long continuous beep, but system works fine

hi all

i recently built an i5 750 system with a Gigabyte GA-P55-UD4 motherboard. when i boot the computer it gives me a nice normal single beep and boots normally. one sec later (as the BIOS displays to screen all the usual normal POST text) after the normal single beep, a lower pitched continuous beep comes on and stays on. however, my system has been running fine without any problems for the last month.

according to the mobo manual "continuous long beeps" means the video card is seated incorrectly. they also describe "continuous short beeps" for power error, which i'm pretty sure i don't have either. i really think my beeping is just "one long continuous lower pitched beep," which unfortunately isn't described in the mobo manual.

anyway, i have the internal speaker removed for now because it's annoying. can anybody recommend any diagnostics tools i could use to attempt to identify the problem (if any)?

thanks,
W