I bought a Toshiba Satellite P755D recently and installed Windows 7 Professional on the machine. It runs great. But I noticed the exclamation point in the yellow triangle icon in the Device Manager next to the Universal Serial Buss (USB) Controller (I'm assuming this is the USB 3.0 controller because mine doesn't recognize devices). Normally, when this kind of thing happens I go to the manufacturer's website and download appropriate drivers and call it a day.
But not this time...
I browsed to my model and found no driver for the USB 3.0 controller. I tried other HW and Utility drivers, thinking they would be bundled. No luck. I tried looking up the motherboard in my machine. Generic name, no luck.
I then called Toshiba technical support and they tried basic troubleshooting, eg, uninstall device, reboot, for auto-installation; no luck. I popped the Windows 7 disk back in and tried to get information that way, no luck.
Finally, the technical support guy said he would look into the engineer's system to see if there was a specific driver available and that's where I'm at. The technician told me that these USB 3.0 drivers come within the native driver pack in windows but that doesn't seem to be the case.
EDIT - See attached screen shots.