My website was down several times per day and when I check the application pool (IIS 7.5), I saw it was stopped and I must restart it manually. How can I setup application pool so that it automatically restarts after an error?
You will need to change the startMode for the application pool your website is running on from onDemand to AlwaysRunning. By default IIS sets all application pools to onDemand.
Source: http://msdn.microsoft.com/en-us/library/ee677285%28v=azure.10%29.aspx
In IIS 8 and above, the start mode setting is now directly available from the Application Pool's Advanced Settings.