Ok - first asswer is yes you can.
2 ways of doing it ...
1 move my documents (or documents in vista to the new drive)
it's easy enough just right click documents | properties and change the path to your new drive
(frinstance replace
C:\Documents and Settings\<your logon name>\My Documents
with
f:\my documents)
windows will even move your existing files to the new drive
http://www.edbott.com/weblog/?p=1371
EXCEPT it's not a good idea to put a system folder onto a removable drive - if it's not plugged in or gets unplugged .... not a happy system
the slightly more involved ... but more system friendly alternative is to use a prog such as this
http://www.microsoft.com/downloads/details.asp x?********=C26EFA36-98E0-4EE9-A7C5-98D0592D8C5 2&displaylang=en
work through the wizard to setup a folder pair (in my example called docs)
set the action to contribute
then create a batch file in your start menu's START folder called something like backup.bat
open a text file in notepad enter the following 3 lines
pause
"C:\Program Files\SyncToy 2.0\SyncToycmd.exe" -r"docs"
pause
this will move everything in your my documents to the portable drive every time you start the machine .....
the first pause gives you chance to abort if you don't want to
the second lets you see the confirmation that the process is complete