Visual Studio generated an error saying that the file web.config is not found when I deploy solution. After that the folder inetpub\wwwroot\wss\VirtualDirectories\80 was empty at all. Also the site is no longer available through the browser, but is somehow available through a SharePoint Manager. Is anyone familiar with this problem?
I came across the fact that Windows SharePoint Services Web Application stucks at "starting" status. After I completed the steps described here the site became available.