okay... i just got this stuff figured out... first... try installing the new itunes and if you already have dont delete anything from the itunes folder... go to this website and download the standalone qt
http://www.apple.com/quicktime/download/standalone.html after its about to finish downloading, then an error message may pop up... ignore it and keep pressing yes... when u get this error message, it meens that it has deleted EVERYTHING that had to do with quicktime before. now go back to the website and download it again... it should work