USB device not recognized

Running XP, I have two external hard drives for secure back-up purposes on my primary PC. Perhaps by indadvertently swopping USB port allocations around (by fitting a 7-port hub etc) these two external drives are no longer viewable or identifiable in Windows Explorer, etc.
However, they still work fine on my secondary PC, also running XP, so the problem is with my primary PC. I get the message "USB device not recognized" when I try to access either of them on that PC.

I'm guessing that somewhere in the registry has 'got confused', but I would much appreciate receiving ideas to overcome this problem
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First make sure your usb ports are ok by trying a couple of other usb devices in them.
Go in to device manager and uninstall all the listings under the "universal serial bus controllers" and restart. That should refresh the drivers. I have seen issues when updating to sp2 where drivers dont update properly.

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rayarnAuthor Commented:
Thanks - as suggested, I got rid of the USB controllers, and on re-start XP re-populated them. The external disc drives then were recognised, and worked for 30 minutes or so, before, while in use,  going AWOL again, back to the "device not recognised message". Odd, and rather perturbing.

Any further ideas, please ?
you could start to look in the registry for entries of those drives, and deleting them
Be sure to backup the registry before you delete anything !
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