This is strange... 
  
I reinstalled everything and did what you said, but the problem remains. 
  
The sound is all crazy, when i plug in my guitar, it sounds like some kind of sci-fi movie, howling and echoing, just distorted, you know. 
  
I then got the idea that i should listen to a song from youtube through the keyboard, i figured that maybe the Line 6 KB37 was broken and the sound was exactly the same, Distored as hell. 
  
I then started my old computer, it,s old and worthless and keep chrashing all the time, sometimes it won,t even start, but this time it did, and the sound was ok, i played with my guitar a few minutes and then it crashed, but at least now i know that the keyboard isn,t broken. 
  
So what can the problem be? Why is the sound all distorted on my new computer?