I ran into this with my new ASUS P5E3 WS Pro MB (it has 12 USB ports)
and Windows 7 64 . I tried all the usual stuff
(uninstalling/reinstalling the USB drivers; updating the BIOS; leaving
the PC off and unplugged for a few hours) but to no avail.

Somehow, I doubted this was a Windows problem because the Boot process
would hang at the point where the USB hard drives were being detected by
the BIOS. If I disconnected them from what I thought were the two
"failing" USB ports on the MB, the PC would boot up fine. But the
devices would still get unrecognized if I replugged them in after
Windows was up and running.

Anyway, I found that if I unplugged all by USB devices, booted up, then
replugged the two drives first, they were detected fine and the drivers
got loaded. I then gradually attached the rest of my other devices and,
bingo, the last one came up with the same error, even though I connected
it via a different USB port.

So, it finally dawned on me that the problem was likely due to the fact
that I had a lot of USB devices (3 HD drives, webcam, keyboard, video
tuner card, 2 UPS's, printer, scanner, card reader etc.) and that the
combined power draw on the USB bus must be exceeding its capacity. So,
I added an external, self-powered 7 port USB Hub and used it for some of
the devices.

The problem went away!!!!!


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user659
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