yeah i know ur problem, i have the same one where i work, i want to access to my admin directory to get some apps and files but i have to restart the sys to log with my user, thats kind of annoying.
well here is my solution, u can create another session and when u change to the another one, ull be asked to log in again by the time u access to the file server, i hope ur understanding what im saying, my english needs practice. just as simple as having 2 users in XP.
if this works let me now man! good luck.