Software :: Corruption On MacBook Display - Random Green Pixels

I have had my MacBook for just over a year. A weeks ago, the display started go weird: - strange shapes started appearing on the desktop - a fluorescent green (like vertical strips of 5 or 6 pixels in a group), sometimes as a shadow of a previous open window, sometimes just random squares or lines. The blocks of green go if i run my mouse over them with the button pressed down. -a fluorescent green light sometimes shines around the programme tiles in the dock. -shadows behind open windows very accentuated and fluorescent green - sometimes text on web pages and documents look garbled - again this goes if i run my mouse over them, and either go or comes back in a different place. Some times i can go a few hours without experiences these problems, other times the issue is there on start up. I ran the quick hardware check, and no problems were reported, a week later i ran the extensive check, and again the system seemed fine.