Today when our sharepoint site suddenly down. I checked on IIS I see all the websites stopped. I restart the server, it runs fine. I checked in event log one of the error is : Event Type: Error Event Type: Information Event Source: ASP.NET 2.0.50727.0 Event Category: None Event ID: 1023 Date: 12/14/2010 Time: 1:56:17 PM User: N/A Computer: SHAREPOINT1 Description: Restarting W3SVC For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp. For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp. Before the site stopped, I was creating a virtual folder for a shortURL, I didn't change anything in the asp.net tab. Then all of a sudden all sites stopped. I found an article on line http://support.microsoft.com/kb/953343 In the article it says "This problem occurs even if you only click the ASP.NET tab and you make no changes to the properties on the ASP.NET tab." I don't remember I click asp.net tab, but I may. My question is in order to fix this, this article told to run a hot fix. But I don't know should I download the hotfix somewhere-I don't see a link in the article, or it's already in our server. The version I found for MmcAspExt.dll in our server the date is different: it is 7/25/2008 11:16. So I wonder is it the one I should run, and how to run a .dll file? Thanks SPUser