I've solved this. It's explained in this article by Microsoft. http://www.microsoft.com/whdc/connect/usb/usbfaq_intro.mspx
I just replaced my hard drive and it appears that in the reinstallation of Windows the "enhanced" USB controller did not get re-installed or re-enabled. I found the enhanced controller listed under "Other" in Device manager and once I updated the driver for it, all USB ports became USB2.
I just replaced my hard drive and it appears that in the reinstallation of Windows the "enhanced" USB controller did not get re-installed or re-enabled. I found the enhanced controller listed under "Other" in Device manager and once I updated the driver for it, all USB ports became USB2.