For starters, if you're not sure what a program does, search the web to get a quick overview before you delete it. Some programs don't allow you to uninstall them. For those that do, on a PC go to the Start menu > select Control Panel > select Add or Remove Programs. You'll be supplied with a list of all the programs you can safely remove from your computer in one click. On a Mac, you can simply drag and drop the program folder into the trash.