'Service Unavailable' Resolution

http://support.microsoft.com/kb/823552

http://guru-web.blogspot.com/2007/10/central-administration-site-service.html

http://articles.icscentral.com/Kb%20Articles/271/823552.aspx

http://www.digwin.com/view/sharepoint-service-unavailable-application-pool-crashes

http://njbblog.blogspot.com/2007/05/sharepoint-error-service-unavailable.html

 

In my case, this issue was fixed by

• Right click on the application pool
  
• Click Identity Tab
  
• Choose "Configurable"
  
• Set to a domain account & enter password / or any user with administrator rights (you can even use the same user with which you are currently logged in)
  
• Restart IIS
  

 

Usually this error occurs when my domain account password has expired and I don't change it and keep on using the virtual machine (i.e. if my account password expires on 14^th November, and I do not shut down my virtual machine or save its state on 12^th November, then I run the virtual machine from the saved state on 15^th November, so it creates a conflict between the logged in password and the actual password which has been changed on the active directory)