sometimes the USB 2.0 bus is assigned the same IRQ in the BIOS as the IDE controller, if an optical drive etc. is EIDE then this can cause issues with devices usually on the same IRQ (usually IRQ11 i think) this shows itself as "your device failed to install correctly" when plugging in a USB drive, the best way to get around this, is to remove the USB hub from Device Manager in Windows, then search for new hardware, on modern motherboards this is usually enough to detec the hub, reinstall it, and wipe the status of attached drives in the process, all without rebooting.
happy trails
