My roommate and I are in the same guild. We both have seperate computers, however, Occasionlly he'll login as himself on my machine to view his PMs and other things. I've noticed that recently i'm not able to logout of his name. I'm stuck as him and can't login as me. To logout i have to completely clear all my history, cookies, and temp files. I'm using Internet Explorer 7 on Vista.

I can provide the site address of the guild if needed.

If he is choosing the option to have IE remember who he is and password it will have issues logging in and out when you want to change accounts. You would likely have to clear the things you are to log him out and log back in.