User Can't Log On

We have a Windows 2003 AD network and Windows XP SP2 workstations. I have
set up a user for a special program and this user has worked fine for several
years. Without any explanation, this user is now logging on to random
machines only at this particular site. One machine logs on fine and the next
two won’t work. As soon as you log on as the user, the machine hangs at
“loading your personal settings�. We have deleted the user and profile
folder on the local machine, and then re-added the user. We have started the
machine in safe-mode with networking and also tried a system restore. We
have even changed cables and switches, just to make sure it is not a
networking issue. One other thing, other user accounts log on fine, it is
just this one particular user. The same thing happens every time. I have
not deleted the user from AD and would like to fix the problem without having
to do this. I am stumped. Any suggestions would be appreciated! Since I’m
not sure if this is an AD issue or a XP issue, I am posting in both groups.
Thanks!