Windows 7: Problem with Usb 3.0 card or enclosure

I recently purchased a usb 3.0 enclosure from silverstone model ts07b and a new 2 tb drive from seagate model ST2000DM001; the usb 3.0 card is from syba model SD-PEX20093. The problem I am having is that when I plug the enclosure into the usb 3.0 slot with the seagate hdd the computer does not recognize it, but when I plug in another 2tb drive from WD (caviar green wd20ears) the computer recognizes it. I know the seagate is not dead because when I plug the enclosure into a usb 2.0 slot the computer recognizes it. Now I need to know what I should replace, should I get a new enclosure or pci card?

Long shot, but try pulling the 3.0 card, uninstalling all the drivers, and then rebooting the system. Then reinstall the card and its drivers fresh. If this provides no solution, there may be damage to the 3.0 aspect of the card itself, as the difference between usb 2 and 3 is extra data path(s) which may have become corrupted in some fashion.