Question : Good one for you! MS Outlook2002 credentials issue..

Many of you know me from here at EE. I consider myself an above average "power user" of all things microsoft, and then some, and networking is what I do for a living, but I've hit a snag here that I simply don't understand.

Background: Windows XP, Office XP, Outlook 2002, all updates/service packs up to date. Been working perfectly for almost a year.
Cable broadband home office
I have a hosts file and lmhosts file that allows me direct acess to Exchange server. All I have to do is open Outlook and put in my password at the prompt. Can't get to .pst files that are on the office server, but that's OK for quick-check/send mail.
I have two different VPN's to office to choose from.
PPTP connection to Microsoft IRAS server through corporate official, supported, access.
Cisco IPSEC VPN to PIX firewall (my own that I have exclusive control over) "back-door" (sanctioned by corp IT).
I have been using the Cisco VPN almost exclusively because it is faster. I can access all servers, my desktop, etc with no problem. Open outlook with the VPN open, and I have full access to all folders, everything works perfectly.
Connect via PPTP VPN and everything still works perfectly.

That was before two days ago. The other morning I was dinking around with my system, cleaning out some old files no longer needed, etc. I ran across an old application that I downloaded a long time ago that switches out the logon screen and the startup screens for XP. Application is called LogonUIBootRandomizer.exe.  Found some really cool looking boot screens and decided to check them out.
Rebooted to see what they looked like
PC was stuck in a reboot cycle. As soon as the boot cycle reached the loginui screen, bam! instant reboot every time.
I tried booting into safe mode - no dice
I tried booting with XP CD to recover - no floppy recovery disk
Ended up doing a complete Repair install of XP
Re-ran service packs, updates to XP
Ran into issue running SP1, pointed to Q327101  where /kernel1.exe was in the boot.ini. Removed that, and everything went fine after that.
Performed repair operation on MS Office, checked all online updates:
There are no updates available for download. Your Office products are up-to-date!

Now here's where it gets odd:
Open Oulook with no VPN open, I get "server not available" and no amount of Retrys will get it to open. I can ping the server by name, and by ip address.
Open Outlook with IPSEC VPN open, I get the username prompt, but it won't accept my password "incorrect username or password" error. However, I still have access to all other servers/services using the same domain/username/password.
Open Outlook with the PPTP IRAS connection, I don't get a username/password/domain prompt because that information was passed through with the DUN VPN connection, then I get "server not available", but one Retry and I finally get my mail.
Outlook Express no seems to take a lot longer to load than it did before, but no other issues noted.

Something in the way the credentials are carried across -by Outlook- has been screwed up on this PC and I don't know how to fix it.
BTW, my laptop with the identical configuration still works exactly the way it did, no problems no matter how I connect or don't connect.

I need some ideas!

Answer : Good one for you! MS Outlook2002 credentials issue..

Sometimes the easiest thing is to re-install. The "deeper" part may be related to DCOM. When you install office it install new DCONM components which may help???