I have two usb ports on two differnt computers that are identical... so it would seem. I just purchased a Toshiba usb drive 3.0 and transferre data from an xp desktop to it without a problem. One of my windows y7 computers can see it fine... My workjorse windows 7"s usb can't see it at all. It's makingme nuts... I also have the same propblem when a client wants me to shook up a mac drive usb ...the same computer won't seeit either... I am usually uploading or lookign at peoples photos fromther hard drive... it's just strage how temermental my one computer is to various usb hardrives.
And I can't update my USB drivers either.. I have been trying all night... rrrr... for this very reason... to get this hard drive to work!!!
For the PC that isn't working correctly, go to the manufacturer's website. In the support section, search for your model. Find the USB driver, and install it.
If that doesn't solve it, go to the start menu, right click on computer, and click properties. Open the device manager. Expand the universal serial bus controllers. Uninstall all of the USB root hubs, and restart the computer. Then plug in the flash drive and see if it recognizes it.
Some guy(link below) had some luck by unplugging his computer from the wall outlet. And then plugging it back in after 5 minutes. However, he should have just pushed the power button while it was unplugged, that would have fully killed it with out the wait.