<rant>
I’ve had it. I’m tired of Microsoft programs taking over my computer without permission. This time it’s IE7 – yes, I know, IE8 is out, but I could not care less. In fact I have not launched IE7 for a long time. Sticking with Firefox, and if I was not so dependent on several Ffox add-ons, the browser I’d switch to would be Google’s Chrome, not Internet Explorer.
So what happened? I don’t know: Firefox is still my default browser, and clicking on the Web works properly, but all the Twitter links I see in Twhirl now open up IE7 – a change I did not want and never agreed to. The last Windows Update was KB955430, which seems to be an update to enable future updates to Vista (!), and is not removable.
I have no idea if it may be the guilty program (suspect not), and I really don’t wish to waste more time investigating. I know it’s fixable, one of those crazy little settings that will only appear obvious after you find it. Why do I have to put up with this? Keep your paws off my system, Microsoft! 
</rant>
“An update to allow future updates” — haha isn’t that classic Microsoft. In their defense, (sort of) I am sick of Apple constantly asking me if I want to install Quicktime in addition to iTunes on my PC.
I’m not sure why your Twitter urls are going through IE7 now, but that red faced guy — don’t I recognize him from the MSN instant messenger program? I love those faces…so MS isn’t ALL bad 🙂
Red-face comes from Windows Live Writer, the one and only MS client app I like, but I guess they use the same in all “live” apps 🙂
I had the same problem with Excel, some links would start my default browser while others would start IE. Since I’m on Win7 I solved the problem by uninstalling IE… 😉