Authentication Issues with Vista Clients

Hello,

I'm having an authentication issue with one specific user...we run SBS 2003
Premium SP2 with everything installed (ISA, SQL, etc). The problem is that
whenever he tries to access the internet, it always prompts him for a
password. When it prompts him, he is able to type in his credentials, and it
works as it should. He can click 'save password,' but it will always prompt
him for authentication whenever he closes and reopens IE. It only will prompt
him for authentication whenever he accesses an external website.

Also, he's having issues with Sharepoint. He is able to browse the
Sharepoint site without having to input a password, but it keeps prompting
for it whenever he tries to open/edit any documents through it. I also have
it setup so he is able to access Sharepoint over a mapped network drive. It's
always prompting for a password to access it that way, too. He is able to
type in his credentials with the mapped network drive, and it allows him
access the documents just fine. If he clicks 'save password,' it will
remember his credentials for a couple of days. Then, just out of the blue,
he'll be trying to attach a file from Sharepoint to an email, and it makes
the computer become unresponsive. He is unable to do anything...can't
open/close any programs or even shutdown the computer. The only thing that
you can open is the task manager, but it won't end any processes if you tell
it to. So, the only way to get the computer to become responsive again is to
turn it off at the power button and turn it back on again. Once he has turned
the computer back on, he's unable to access Sharepoint over the mapped
network drive, again. It tells him that it couldn't reconnect the mapped
drive, and whenever you try to click on it, it says "access denied." The only
way to restore the connection is to delete the drive and re-create it. Once
the drive has been recreated, it will pop up and ask for his credentials. I'm
thinking that the computer becomes unresponsive because it's trying to
authenticate over the network to get the file.

At first, I believed that it was an issue specific to his computer because
whenever I tried accessing the web or Sharepoint over a mapped network drive
with any of the other computers, it worked just fine. I tried troubleshooting
the issue by completely deleting his profile from that computer, so it would
recreate it. That didn't seem to work, so I did a system restore back a few
months whenever he wasn't experiencing this issue. That seemed to be the
ticket, as it started working again. However, I was wrong. A few days later,
it started happening again. So, I decided to completely format his computer.
It worked great for the first two days after I formatted it, but it's back to
doing the same thing again. Now, that I've gone around to the other computers
and logged in with his account, I've noticed it's doing it on them, too. So,
it's definitely not an issue with a specific workstation. We have three
workstations that run Vista, and one that runs XP. Just now, as I've been
typing this message, I've realized that the Sharepoint issue is happening on
my domain administrator account, too. It seems to happen with his and my
account on all three Vista workstations and not the XP workstation. I've been
checking the Event Viewer on the workstations and on the server. There are no
errors that stand out.

However, the issue where it prompts for a password to access the internet is
only limited to one specific account on the Vista workstations (not the XP
workstation). It doesn't prompt me for a password on my account. Then, the
really strange thing is that there is a third user that has absolutely no
trouble at all authenticating to Sharepoint or the internet on any of the
workstations.

So, to summarize, the Sharepoint issue is only on my domain administrator
account and one other user account. The internet related issue only happens
on one user account...and, then, there's another user who has no trouble at
all accessing anything. Those are the only three users accounts on the
server, so I have no other accounts to go by. The only thing different about
that third user who has no troubles at all is that it is a new user account
that was created whenever he began working there last month.

So, I'm at a loss for what to do, as the issues are so inconsitent. The only
common ground that I can find is that the problems are all happening on
Vista. We've had Vista installed ever since it came out back in February, and
it has been working great up until a few weeks ago when these authentication
issues started happening. Does anyone else have any ideas? I'm to the point
where I'm so frustrated that I'm fixing to downgrade all the clients back to
XP.

Thanks.
.

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