Upon start up, programs start up without my opening them. How to stop this?

System Preference > User & Groups > (your current user) > Login Items

Highlight the apps you don't want to launch on Login, and click the "-" (minus) symbol below the list.

If Scotch_Brawth's answer didn't apply,

Were they open when you shut down?

Resume will reopen any open applications when you restart.

You can turn that off in the General System Preferences