You might have to change BIOS settings if you boot from an external port but you can do it.
Is your OS on this HDD?
My winXP SP2 OS is on the hdd. it was to the desktop i owned. Just afraid if i load it i might not be able to access user account files.
to transfer so i can wipe the drive.
I don't see why you shouldn't be able to access it.
If I assume, "my hot swappable shell" is a external harddrive shell which is able to "host" a harddrive which you then can connect to the new computer you have, then you should be able. Don't know if it makes a difference, but for convenience's sake, plug the USB cabel after you've loaded your OS.