This is more just for a reference for myself and for others, below is a link that can resolve the "Unattended Service Account Application ID is not specified or value is invalid value." error that you might see in the Health Analyzer Reports in Central Adminstration. I suggest creating a new Target Application ID to keep it seperate from existing Target Application IDs that you have in your SharePoint farm. Enjoy !!!
http://technet.microsoft.com/en-us/library/hh204612.aspx
