U2711 USB Ports not working

I have a Dell U2711(digital) monitor and the USB side ports are not active.  I read some of the previous posts, and ensured that my USB upstream cable is hooked up.  I verified that the USB port that the upstream cable is plugged into on my desktop XPS is working just fine.  Lastly, I tried changing the upstream cable, to see if something might be wrong with the cable - but no luck.  I am running Windows 7 Home Premium 64-bit for my operating system.  Monitor driver is version 1.0.0.0, dated 07/24/2009. I recently reformatted my hard drive, best guess is that some settings may have changed leading to this issue.  Any thoughts where I might look next to resolve this issue?  Thanks!