Not sure if this is the right area to post in, but...
If a USB device (any USB device) is left plugged into my computer and I reboot, the IDE scan does not occur, thus my DVD player or any other IDE devices do not show up.
However, my system disk (harddrive) is IDE, and there is usually no problem with the computer booting --the DVD device and secondary IDE disks just don't show up. Once in a blue moon the computer won't boot if a USB device is left plugged in; there is no error message, just a blank screen in "hang."
So, the simple problem: USB devices plugged in on boot-up prevent my IDE DVD player/recorder from being usable.
If I unplug all my USB devices, there is never an issue at boot up.