http://forums.techarena.in/xp-print-fax/973355-2.htm mentions an interaction with Logitech bluetooth software. Of course, the case with you might be different. I'd say: try it after booting in Safe Mode to see if that makes a difference.

You can uninstall Microsoft Fax from Control Panel>Add/Remove and reinstall it from the XP CD the same way: it's listed in the optional components. It's not possible to download it, I think.

Kees