Really need help for my code!

The message says - UnityEngine.Application' does not contain a definition for Loadlevel’ why?

What I have checked-

EVERYTHING! (On the code at least)

What I think it may be-

No clue.

Did you even bother to check the documentation where it says that Application.LoadLevel is obsolete?

Use SceneManager.LoadScene instead:

yes I have. I’ve tried it both ways and I have found there to be no difference (by the way I’m using unity 4.7)