I have a laptop running Win2K which usually plugs into a corporate
domain, a home PC running XP Professional which is configured as part
of a workgroup, and a linksys router between them providing shared
DSL.  I want to back up files from the laptop when it's at home & not
on the domain, to the home pc, or just drag files from one machine to
the other.  How do I do this without having to reconfig the laptop
temporarily as a workgroup?

Here's some quick and dirty (and free ;) ) stuff for you to try while
you
wait for a more thorough answer from a "real" GA type.

This should be possible, but I'm doing this from memory and with
Windows
File & Printer sharing, things can go a little wonky.  Anyway, it's
best
(i.e. least likely to annoy your network administrator) if you push
files
from the network laptop to your home machine (that way you don't have
to
enable File & Printer sharing on your laptop, which will not make you
friends back at the office).

Assumptions:
-You already have File & Printer sharing enabled on the XP home
machine.
-You already have a directory shared on your home machine.
-Your laptop gets its IP from a DHCP server at work, and from the
Linksys
at home.

It's best if you don't have password protection on the XP share, but
not a
big deal if you do (it shouldn't matter much from a security
perspective if
you do, since you have the Linksys protecting bad guys from coming in
- and
if you think that password is protecting your kids from looking at
your
stuff, you're mistaken ;) ).  At any rate, there are lots of ways of
doing
this (through Windows Explorer, with batch files, Network
Neighbourhoud,
etc.), but for now let's try it this way:

Click on Start, Run
Type "cmd" (no quotes), then hit <enter>
You should get a dos prompt
Type "net use x: \\nameofhomemachine\nameofshare" and hit <enter>
If it maps successfully, away you go - you now have an X: drive that
you
can use to copy files back and forth.
If it asks you for a password, try entering the password (if you use
one)
for the main account on your XP box.  If that doesn't work, try the
following format instead:

"net use x: \\nameofhomemachine\nameofshare /user:administrator"
(where
administrator is the name of the user on your XP machine).  It should
then
prompt you for a password for that user.  Enter it, and you should be
good
to go.

Type "exit" <enter> and you should be back in windows land, and able
to
access the share on your home machine from your laptop as the X:
drive.

Oh, you may find you need to substitute "name of machine" with the ip
address of the home machine, which you can find out by doing this on
your XP box:
-Type "cmd" (no quotes), then hit <enter>
-You should get a dos prompt
-Type "ipconfig" and hit <enter>
-It should spew out a bunch of stuff - your IP address is probably
something like 192.168.1.100 or 192.168.1.101
-Type "exit" <enter> and you should be back in windows land.

If you need to know how to add local accounts to XP, enable File and
Printer sharing, share directories, edit your lmhosts file to add the
ip address of your XP machine, make the share permanent, etc., feel
free to clarify.

At first set your windows XP workgroup name same as your laptop domain
name.

If your laptop configure to use a dhcp server, your home computer must
be set as it.
If your laptop had a static IP on domain, you must configure your XP
as below:
IP Address: same as laptop, just last octet must be diffrent (for
example plus 1)
IP subnet: same as your laptop
IP gateway: same as your laptop IP Address (not gateway address)

(maybe need to restart your XP)

Now, in My Network Place in Computer Near Me you must be find your
laptop computer. If you can't find it, in address bar of my network
place type \\your-laptop-name and press enter.

Maybe needed you logon to your laptop computer with a local user (not
domain user).

Good Luck,