I know a little about hardware, not a whole bunch...
I would try flipping the set up so that the opposite drive is set up as the slave. If you look at the back of the drives you will find a set of pins with some small jumpers arranged on them. there should be a description of how to place the jumpers so that the drive is in slave or master mode.
It's my guess that BIOS will look for the master drive and boot from there. since you've switched them, all will be rocking. Worst thing that can happen is that it won't start at all, at which point you switch things back.
Don't open your computer case on a carpeted floor, and make sure to ground yourself against the metal frame before touching any components... A static spark can nuke your hard drive.
Best of luck... I make no guarantees.... but it's what i'd try...
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