Whenever Windows updates, it sometimes/most times downloads installation files, and then uses those files to install the update onto the OS (correct me if I'm wrong on this assumption). What I want to know is if those files aren't crucial to the operation of the OS and can be deleted. If so, then where can I locate those files and delete them?
It's safe to delete the SoftwareDistribution folder which keeps the stuff you describe.
Read this Microsoft KB article which describes how...