I have installed Exchange 2007 STD on a very beefy Windows Server 2012 R2 PC. Applied all of the updated and rollups and all was working well, UNTIL I tried to use OWA which of course DID NOT. Got 404 errors, yada yada yada. Much to my surprise I read that I should have protected Login.aspx (I guess), whatever. In reading articles it appeared that my virtual Directory was damaged and saw that I could just remove and recreate the OWA directory via the Exchange Management Shell.  YAY!! Boy was I stupid to think something would be so easy with Microsoft. So I followed the easy commands to remove which worked great. What didn't work great was the recreate which throws the following Error EVERY TIME. Cmdlet I used :New-OwaVirtualDirectory -OwaVersion “Exchange2007″ -Name “owa (Default Web Site)”. Error it throws:

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VERBOSE: New-OwaVirtualDirectory : Beginning processing.
VERBOSE: New-OwaVirtualDirectory : Administrator Active Directory session
settings are:  View Entire Forest: 'False', Default cope: 'xxxxxxxxxx.com',
Configuration Domain Controller: 'XXX-XX01.xxxxxxxxx.com',
VERBOSE: New-OwaVirtualDirectory : Searching objects "XXX-XX01.xxxxxxxxx.com"
of type "Server" under the root "$null".
VERBOSE: New-OwaVirtualDirectory : Previous operation run on domain controller 'XXX-XX01.xxxxxxxxxx.com'.
VERBOSE: New-OwaVirtualDirectory : Processing object "XXX-XX01owa".
VERBOSE: Creating Outlook Web Access virtual directory "Default Web Site" on server "XXX-XX01.xxxxxxxxx.com".
New-OwaVirtualDirectory : An error occurred while creating the IIS virtual
directory 'IIS://XXX-XX01.xxxxxxxxx.com/W3SVC/1/ROOT/owa' on 'XXX-XX01'.
At line:1 char:1
+ New-OwaVirtualDirectory -OwaVersion "Exchange2007" -Name "owa (Default Web
Site) ...
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
~~~
+ CategoryInfo          : InvalidOperation: (BPR-DC01owa (Default Web Sit
e):ADObjectId) [New-OwaVirtualDirectory], InvalidOperationException
+ FullyQualifiedErrorId : 52FEE109,Microsoft.Exchange.Management.SystemCon
figurationTasks.NewOwaVirtualDirectory

VERBOSE: New-OwaVirtualDirectory : Ending processing.
=======================================================

I really need to keep this as transparent to my clients as possible. I don't want to have to re-install IIS if I can avoid this (I have Symantec Endpoint and SMSMSE running on it also). Also if I have to re-install CAS role, does that affect my clients ability to use MS Outlook 2007? Are their Mailboxes and email safe or is this in jeapardy too. If I uninstall the rollups will that restore OWA?  Looking for any help. Please don't suggest upgrading Exchange as that is not an option. Thanks for any help.