For backing up/formatting.

Normally on a linux system you look in "/home/user/.<program>/".. seldom you need to go to another folder. To install and uninstall you could use synaptic package manager to check or uncheck the programs you like.

on a windows system you normally look in "/program files/" but pretty often you need to look in "/system/" or "/system32/" or "/My Documents/" or "/user/application data/" or on "c:\" or on "d:\"... e.t.c. and then you need to go to the registry sometimes and change some settings there. If you clogged the system you need to format and all your settings are gone making it paintful to setup again. Looking fo drivers on the internet.. e.t.c.