Software Deployment

Hi All I am working on this application and it works fine for silent switches. I have to install product key with installation and it seems like it installs product key but after installation i cant find product key any where. i searched in help/about. also in registries. so i am not sure why it does not installs product key with visual studio installation. Also there are lot of components remains behind after uninstall. These components are 1) asp.net mvc3 2.asp.net web pages 3.silevr light 4 sdk ,silver light 5 sdk ,sql server 2012 components---command line utilities,data tier app frame work, express local db ,management objects, native client,sql compiler service, sql script dorm, sql launguage service, and so on. so is it a better idea to remove these all components after uninstall? because almost all of them has msi's. or is there any purpose for these components to be left behind. Appreciate your answers. Thanks