How to add and remove programs from startup windows 8 ?

Disable / enable program on startup Wndows 8

(right click) Windows Toolbar -> (select) Task Manager -> (select) Startup -> (right click) application -> (select) disable / enable

Add programs to startup Windows 8

From Run box run: 
%APPDATA%\Microsoft\Windows\Start Menu\Programs\Startup

or type in Windows explorer:
C:\Users\(your domain name)\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Startup

or look here.