I just installed Win XP and now wherever I go I sign in with the messenger passport instead of the passport I need for that area. 

I do not want my one passport to be the Msgr passport what do i do

just remove the Passport.Net\* entry from your keyring

http://messenger.jonathankay.com/allsteps.aspx?ID=2

Step 5: 

step 5 shows the right box

just remove the passport.net\* entry in there

and the saved passport is gone