I have a program called RevoUninstaller. It is great. It has a section that allows me to view what programs run when I start up my computer, and enable or disable them. It's main purpose is to find and delete all files left over after you delete a program. Most programs, when they are deleted, leave files on your registry. This finds those files and deletes them. I love it and would recommend everyone downloading it. It's
free! 
If you need a little more convincing, this will allow you to get a free trial multiple times. Like above, when you download a free trial of something and the trial is over, you usually remove the program. Well the program leaves files on your registry so if you tried to download it again, it will know that your computer has already had a free trial. This program removes those files so you can get a new free trial