Why is my windows installer not installed correctly and how do i fix it?

[Windows Central Question]

i have windows 7 and i was in safe mode trying to uninstall unwanted programs and every one i clicked gave me the error "The windows installer service could not be accessed. This can occur if the windows installer is not installed correctly." I also cannot seem to install windows updates and i was wondering if this was causing the problem? Ive tried to go into services.msc and click windows installer to change it to manual but it was already on manual.