Recently alot of popel have ben complaining while watching any sort of media online that uses a flash player that the screen splits in two and show two images. Noteably this effected alot of people who use youtube. Read below on how to stop youtube showing is two images/screens.
This seems to be an issues with the version number of adobe flash – Flash Player 10_1r53_64.
To resolve this issue use the uninstaller provided by Adobe http://kb2.adobe.com/cps/141/tn_14157.html , and then install the previous version, 10r45_2 (taken from the archive provided also by Adobe – http://kb2.adobe.com/cps/142/tn_14266.html