dual booting windows 2000 and xp

[Guest]

i am trying to install windows wp in my external usb hard
drive. and at the same time keeping my windows 2000
operating system in my c drive.
"My conputer" shows my extenal hard drive as "F". When i
reach the windows set up screen it displays a list of
existing partition: C and F partition are listed.
I select F and press <enter>
I get the following message: " Start up program cannot
gain acces to the disk. Disks attached to SCSI adapter
that wasnot installed by your computer manufacturer or to
secondary hard drive controller are typically not visible
to the start up program unles special software is used
Now, when i turn on my pc, it shows a boot up menu: windows 2000 and xp
i appreciate any hel

 

[CS]

i am trying to install windows wp in my external usb hard
drive. and at the same time keeping my windows 2000
operating system in my c drive.
"My conputer" shows my extenal hard drive as "F". When i
reach the windows set up screen it displays a list of
existing partition: C and F partition are listed.
I select F and press <enter>.
I get the following message: " Start up program cannot
gain acces to the disk. Disks attached to SCSI adapter
that wasnot installed by your computer manufacturer or to
secondary hard drive controller are typically not visible
to the start up program unles special software is used"
Now, when i turn on my pc, it shows a boot up menu: windows 2000 and xp.
i appreciate any help

You can not install XP to an external USB hard drive.