I first noticed that a user was not able to launch Excel or Word by double-clicking on an attachment from Outlook. Nothing happens at all after the double-click. Then I noticed that the same behavior occurs when I double-click an Excel or Word document within Windows Explorer. If I first open Excel or Word and then double-click the document, it loads up fine, however, so that's her workaround for now. I've already tried repairing Office XP and also removing and then recreating the file associations. Powerpoint documents launch Powerpoing just fine.