I work in VS 2008, and every time I made a change to my code / html I had to stop the ASP.NET development server – apparently called Cassini.
This was a little irritating as you can imagine, after scouring the internet every time I had a chance for a few months, I was ready to give up, I even posted on a few forums.
Then I found a great site that spoke about nothing to do with the server, and guess what it is working. It has to do with how .net is dealt with on you machine, and it obviously assumes you are not a coder by default.
On the MSDN forums I found a reference to the Microsoft knowledge base: KB911272. In summary
Essentially the HKLM\Software\Microsoft\ASP.NET\FCNMode determines how ASP.NET is dealt with as an app on the box.
Initially setting this to "0" fixed the problem, but this caused a UNC share problem, so then I set it to two after finding this great item
And now I can change my code and run on the fly.