This is just one account... not associated with any others. I also found something interesting... it seems that Windows XP has just forgotten the domain credentials alltogether. When I tried to do \\adserver on my coworkers machine, it asked for his password... when I did it on mine, it let me on to the \\adserver share. So it sounds like Windows XP (and essentially Outlook) forgets the domain credentials and prompts for them whenever my coworker tries to authenticate with this AD credentials. This is odd since he is using the same XP image as 70+ other people, and he is the only one with issues.