Excel 2010/Win XP SP3 - 'Save As' on local machine

[Milo Minderbinder]

have you got any mapped links to network drives on that machine? Try deleting them
On older versions of Office this was an issue - it may give some clues
Microsoft Office stops responding when you try to open or save a file

in your case it could be worth trying this, though its not exactly your problem
You cannot save documents to a folder or change the permission settings of folders on a SMB 1.0-based remote server from a Windows-based computer that has security update 980232 (MS10-020) installed