I am having problems with my music collection, after burning all of my music to the computer I organized it into folders and placed it in the iTunes Folder. Starting on a new computer now. I can get my music from old computer?

I am having problems with my music collection, after burning all of my music to the computer I organized it into folders and placed it in the iTunes Folder. As of now i realize this was a mistake. Starting on a new computer now. I cant get my music to transfer from the itunes folder on the old computer? I keep getting error "Can't Read from the source file or disk." Whenever I got to folder properties its always checked read only. But when i play the song it works just fine. Im sure this is just because I added music into itunes folder but is there anyway to fix it?