title: HTTP Error 503. The service is unavailable under simple ASP.NET 4.0 web site
body: <p>Something strange happened on my local laptop: my web site that worked locally for a long isn't launched...</p>
  <p>Trying to localize the problem I've created a simple web site with 'index.html' file only. It works fine under ASP.NET 2.0, but when I switched App Pool to use 4.0 - it stopped to work.</p>
  <p>When I open web site in browser it shows the following error:</p>
  <blockquote>
  <p>Service Unavailable</p>
  <p>HTTP Error 503. The service is unavailable.</p>
  </blockquote>
  <p>And causes App pool to stop work also... In the system event log in &quot;applications&quot; section I have:</p>
  <blockquote>
  <p>The worker process failed to initialize correctly and therefore could not be started.  The data is the error.</p>
  </blockquote>
  <p>Please advise. Can't find anything related in Google... :(</p>
  <p>P.S. I have VS2010, Windows Vista x64, last updates installed, VS SP1 is also installed...</p>