Device failure sound during startup

You know the Windows sound that plays when you have a removable device failure? It's like 3 low pitched dings. I'm getting it at startup but the thing is that I don't know what device is doing it. I have 2 keyboards, a Razer Orbweaver keypad, a Razer Naga, a small flash drive, an Xbox 360 controller, a Soundblaster Omni external soundcard, and a Turtle Beach headset that uses USB only to power the headphones but uses 3.5 for the sound.

Nothing is having any trouble right now and I can't figure out which device is doing it. So what should I do?

Have you tried unplugging the USB devices and trying each, one at a time?

That used to drive me crazy as well till i finally figured it out (for my case - yours may be same)

After Windows installs the USB Mass Storage drivers it then goes to install a WPD driver for the USB device. Don't know why, but the WPD install would sometimes, not always, fail - though that never caused me any problem - other then driving me crazy wondering what the System sound was for

Next time it happens, Right click Computer->Manage->Event Viewer->Windows Logs->System.
Then in the right pane click Filter Current Log, check off Warning and Error. Click OK. That will get rid of all the Information messages. See if a WPD driver isn't loading