That the IDE Drive on all M'Boards will become the Default Drive and the system will no longer boot as the necessary files will not be present on the IDE Drive.
You can perform a Repair Install after fitting the IDE Drive to make the system work again but this will lose you all of the Service Packs & Patches that have been applied since your OS was originally installed.
Generally Speaking it's easier to use the IDE Drive in a USB Caddy but remember that these are not an [b]Always On[/b] thing and should only be run as required.
The other thing is that the IDE Lead is either a 40 or 80 way Cable not Pins as both the IDE interfaces only have 40 pins or more likely 39 Pins.
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