My PC is displaying these one inch thick vertical blue lines that flicker and over the color white show as yellow. I was just wondering if anybody could help me resolve this issue.

Screenshot:

HEY, CAN ANYONE HELP MEEE!!!
About a week or 2 ago all my videos (avi, mpg etc...) have stopped working, on some the audio is still there, and there is a blank image, i have tried downloading codecs etc... no joy. Also seems to crash my pc when i try and watch some videos. Any ideas?

cheers

Toby