We all know the temptation to start clicking as soon as we see our desktop wallpaper and icons appear on our computer screen. It is best to wait until all startup programs are loaded before trying to use your computer though. Even after the desktop is displayed your computer may still be loading programs in the background as evidenced by the spinning hour glass mouse cursor. If you try to open programs while the computer is doing this you are actually giving the CPU more work to do and could make the program you are in a hurry to run startup even slower.
If your computer is loading too slowly you can always manage startup programs with CCleaner. In any case it is best to be a little patient and wait for your computer to completely finish booting before you start running programs.