My PC can't open any sort of script

My pc cant open any sort of script:

by javascript: ERROR

by C# script: it opens but i cant do anything because the whole “paper” is gray

by Boo script: Nothing happens but i get an error from UNITY4.3D =

“unable to open Assets/Scripts/NewBehaviourScript.boo: Check external application preferences”

The funny thing is: I could open C# last time without a problem

I ran into an issue like this before. With me it turned out to be some kind of issue with MonoDevelop.

I went here [MonoDevelop][1] and selected Packages, then downloaded and installed the .NetFramework 4.0 and GTK# for .net2.12.22. That seemed to fixed it. Might give that a shot. Be sure and close out of Unity while you install this stuff to be safe
[1]: Redirecting…