This works just fine, you'll get a selection window and you'll be able to
set up the default selection of which OS to boot up on. Also, if you have
multiple drives, you can boot up on one OS in order to backup the partition
for the other OS.

you have to move the jumpers around.make current drive slave new drive master
to copy everything from c to new drive.then switch them
back.u can move jumpers without removing drive but its VERY hard. u could
just put the drive in next to the other drive.& move the ribbon wire & power
wire.this can be done without taking out drive.u use the windows cd if its a
full windows cd install on new drive.but u wouldn't have copy of stuff on
c.anyway u move ribbon wire back to first drive to use it.or if u have a
backup system that connects to usb use that to copy c to new drive then set
new drive to slave.BUT i have 1 drive in
pc i set it to master and windows won't work.i had to remove the jumper
so the drive u have in ur pc might not have jumper.its easyer to put jumper
on with drive out of pc.its not hard to remove drive.just 4 screws
2 wires...just take ur time don't rush........

   The easiest way to do that would be to "clone" the
   partition containing your currently installed OS and
   boot files over to another hard drive and to set up
   the boot.ini file for multi-booting.  But first, you must
   choose which drive you want to hold the clone -
   the 120GB PATA drive or the SCSI drive.  If it's the
   PATA drive, you'll find a lot more people who can help.
   It currently takes magic to boot Windows from a USB
   drive, so forget about that.

   Secondly, do you have an empty 5 1/4" bay to house
   a "mobile rack" or "drive caddy"?

   Thirdly, do you have an unused backplane expansion
   slot and would you find it convenient to house your
   bootable backup drive in an external case?

*TimDaniels*