Unable to remove deleted Session Hosts from RDS Windows 2012 Deployment
Unable to remove deleted Session Hosts from RDS Windows 2012 Deployment Very good article: http://dave.harris.net/unable-to-remove-deleted-session-hosts-from-rds2012-deployment/
How to remove applications with issues
If you have an issue with an application that will not un-install as its referencing to missing MSI files etc then use the Microsoft Windows Installer CleanUp Utility http://support.microsoft.com/kb/290301