There's a "default beep" (as defined in System Sounds) that emanates from my computer every so often.

It kind of goes like this (where each number is a "default beep" sound): 1, 2, 3, 4, 5.

So there's a distinct pattern to it.

I thought I had this figured out a way to figure out what was happening by going to

Control Panel->Ease of Access->Ease of Access Center->Replace sounds with visual cues

But that just isn't the case. Whichever window I click on, that one displays the visual queue when this happens.

It's driving me crazy, and I can't figure out which program is causing this.

Update: it appears to only happen on one user profile on the computer...does that help?

Update 2: Discovered that this sound was coming from a utility on my laptop called ASUS NB Probe; I'm certain that it is emanating from this program because the error message displayed by it changes in sync with the sound playing. Apparently the S.M.A.R.T. feature of my hard drive was reporting an issue. It displays the issue for a brief second and then makes it disappear, I'll have to keep watching it to see what it says, but I believe is says something about a read.

I have an external hdd connected with eSATA to a container of sorts (BlacX) that you can plug two hdds into. I have one hdd attached and it's a Western Digital WD1001FALS - 00E8B0

Thanks again! Now I'm off to go around the Internet and report on this...since I posted it so many places!