A couple of my users are being prompted for their password when they attempt to open up Office documents in Outlook Web Access. If you enter the username and password several times you can view the document but it only does this for Office types; PDFs, TXTs, etc. open up just fine. Oddly, if you hit 'Cancel' when prompted for your password you can open Word documents.
Most of the PCs in the office have no problems opening up Office documents in OWA regardless of whether they only have Office 2003 or Office 2010 or the Word and Excel Viewers.
I've removed and re-added the PC to the domain, re-installed IE8, run the MS registry fix that's supposed to set the file types (it's never had a problem opening up a document locally or from the network though), and then also did a number of OWA server fixes like adding the MIME types to IIS, adding the MIME types to Internet Message Formats in Exchange System Manager, and setting the authentication types on the Exchange Virtual Server.
So, because it only affects a few machines, I think it's a local thing, but I can't figure it out either way.
Ideas of what else to try?
It's Exchange 2003 running on Server 2003 SR2 and the workstation in question is running XP SP3 with IE 8.