Networking help

[alpha2k]

I've been doing roaming profiles stuff in school, wich btw I really HATE roaming profiles.....anyways, we are doing files and folders shareing with permissions stuff, so I have been messing around with my 2 pcs here at home and file shareing and permissions and such, but I have to start > logoff each time to get the name/password screen to come back up for logging into the other machine as a different user.

My question is, is there a way to like log off the network without haveing to go thru all the start > logoff then logback on process, to get the user name/password on the network? Like ipconfig has a release and renew command line, is there somthing similar for what I wanna do?
I'm just using 2 xp pro machines, no server or anything is involved.