2011 Macbook Pro not detecting usb to vga display

Hi All,

Went to best buy and was told that I could have my 2011 Macbook Pro connect to two external monitors, one with the mini display to dvi and the other USB to VGA using the USB 3.0 adaptor even though my computer has the 2.0 port. I am having no problem with the mini display to dvi but am not getting anything from the usb to vga when trying to detect the display.

Has anyone dealt with this before or have any ideas if this is even possible to do before I waste my time any more?

Thank you

Dan