Visual-studio – Can’t cleanly install Visual Studio 2008

I had a bare-bones install of Visual Studio 2008 on my computer, which I think I picked up from installing SQL Server 2008. I later installed VS2008 Standard edition, but I couldn't create any new projects (I only had like 1 or 2 unusual options under C#). So I uninstalled all of the VS2008 stuff that wasn't the Standard edition, which allowed me to create new projects, but I couldn't debug (probably because one of the things I uninstalled was a debugger).

So I thought I'd start over, fully uninstalling and re-installing VS2008, but doing so gave me a bunch of errors when I tried to start the app, and my WPF XANL designer didn't appear any more (I just got the regular XML editor). So I followed this article to completely uninstall VS2008, but after doing so and re-installing, I still don't have a WPF XAML editor with a designer.

So clearly I have something sticking around, as I've managed to install this copy of VS2008 Standard before, but I'm not sure what to do to get a clean install.

I'm running Windows 7, and I have VS2010 Beta 2 and SQL Server 2008 (and 2005 express, which I accidentally picked up on my latest VS2008 install) installed as well.

How can I get a clean uninstall and re-install? Or can I get the WPF designer preview back some other way?

Update
When I right-click on a .xaml file and select "View code", I get an error message that says:

Ther is no editor available for ".xaml". Make sure
the application for the file type
(.xaml) is installed.

It's pretty descriptive of the problem, but I thought it could shed some light.