If you are getting a split screen with a GREEN vertical line across your screen. RIGHT CLICK the Video you are watching on YOUTUBE. When it opens up LEFT CLICK , SETTINGS. A small box with ADOBE FLASH PLAYER SETTINGS should appear on screen. Go down to the LEFT bottom of the LITTLE BOX and click on the small T. V. screen. UNTICK THE BOX next to ENABLE HARDWARE ACCELERATION, then click on close.  Go out of YOUTUBE then come back in to view a Video. It should have NO lines on it. Good Luck

Gerry C, February 2011