Obviously, I'm at a loss to explain why Microsoft has failed to offer a consistent platform for development and I feel quite aggrieved about it. If I hadn't already boycotted Internet Explorer this would be a pretty good reason to start.
On the assumption that some other piece of software has by accident or design disabled - or had previously enabled -
- Microsoft Outlook 2007, installed for the first time on this computer this week.
- Word 2007, also installed this week for the first time.
- Some random Windows update I installed last weekend.
- Access 2007, installed two weeks ago (but I think I would have noticed sooner if that had caused this change).
- Removing something malicious with Spybot. I think it removed one or two dubious registry entries left over from an infection of Vundo/VirtuMonde last year, so it's unlikely but there's an outside chance of an effect.