Reminder for Others - VS.NET 2005/2003 ASP.NET Compatibility

As Dave Totzke has noted in the past, one of my reasons for blogging is to remind me of things that I'm likely to forget in the future and that I had a difficult time finding solutions for in the first place.  This particular blog is intended to help both me and anyone else trying to run ASP.NET.

The situation is as follows:

I'm running both VS.NET 2003 and VS.NET 2005 on the same machine, because I'm doing a little bit of work in both environments.  This particular project had me creating a web service in VS.NET 2003.  Tried to debug the web service and ran into a problem, that being an "Error while trying to run project: Unable to start debugging on the web server" message.  Now my memory was jogged.  The problem is related to the fact that the installation of 2005 meant that all ASP.NET apps were running using the 2.0 version of the framework.  So my search became more along the lines of "how do I fix this?"

The ultimate answer is to run the aspnet_regiis command for the Framework version that you want to debug against.  But that isn't the best solution.  An an alternative, take a look at Denis Bauer's ASP.NET Version Switcher utility.  Using this tool, you can target particular virtual directories making them work against the Framework version of your choice.  Very nice if you're mixing your development platforms.