This is a larger issue than just my computer but for the sake of detail my recently built computer is where the problem occurred. I borrowed a friends external Western Digital hard drive to MOVE DATA from my old laptop to my newly built desktop. I was copying files from my laptop fine and as soon as I plug the hard drive into my new computer it says USB device not recognized. I've already plugged many devices in the same spot. The real issue is that now when I plug the hard drive back in my laptop it comes up as unrecognized even though it was working fine before. I plug it into my parents laptop and even my friends mac and it is still not recognized. Sadly this stigma has now moved to my printer after plugging it into my new computer and it will come up as unrecognized on any other computer.

I went through the whole process of checking if my drivers were updated, turned my computer off, but even with the help of my friend, who essentially built my computer for me, we couldn't figure out the problem. Any ideas at all would be great, this has a been an issue for quite some time. Do you have a backup?
No joke. You MAY have a virus that got into your USB drivers.Are you using the cord that came with your WD Hard drive? Try using another USB cord or a Dual USB Data Cable. Works for me. Some threads I have read on WD sites were about certain protection softwares interfering with the Hard drive. Worth a shot to see if it would make a difference.Thanx for the ideas, i will check into the whole virus issue and call my guy on that even though I do have an anti-virus, but to be safe I will give that a looking into

Its a friend's hardrive so yes I'm assuming the cord came with the WD hardrive, i will look into other usb cables, that would help a bunch if the problem was that simple.
But just to REITERATE, this happened to not only my friend's hardrive but my printer which uses a usb connection as well.

Again thanx for the replies. This seems to happen to a lot of people.
http://answers.microsoft.com/en-us/windows/forum/windows_vista-hardware/usb-device-not-recognized-error-keeps-popping-up/6be4581d-8fbd-407f-815e-b475c35ca586
Read the whole thing, you might get lucky & the simple solution works for you.