Today I tried all things in vain to try and install ASP.NET MVC 1.0 on to my machine and it just kept failing.
Possible causes, upon Binging focused on conflicting Visual Studio 2008 addons. Among the list of such addons, I had PowerCommands. But, despite uninstalling it, mvc installer complained.
Then I begun uninstalling other possible addons (not listed in the mvc installer readme file). The first to go was SlickEdit gadgets.
Lo and behold, the MVC installation was successful.