Exchange 2000 sp3 removal halted by krbtgt mailbox

Hello.

Overview:  Cannot uninstall exchange becaues mail enabled object still exists on information store.

System Description:

Window 2000 sp4 server
Domain controller
Exchange 2000 sp3

What has been done:

1)  Followed KB article:  http://support/microsoft.com/kb/307917 to remove exchange
2)  Inserted Exchange Disk into server and tried to remove--received above error in overview
3)  Used following article to find mailboxes not listed in esm:  http://support.microsoft.com/kb/279202
4)  Found that the krbtgt account, among others--which have been move or deleted, has a mailbox associated with it somehow.

Questions:

1)  Is it normal to have a mailbox associated with this account?
2)  Knowing that the account handles authentication and has some pretty fundamental system responsibilites, is it bad to remove the mailbox from the account to resolve this problem?
3)  Is there another way to look at this problem that I'm missing?

Your input is appreciated

Scott