Out of nowhere, my Toshiba Tecra R950 laptop has recently started wildly flickering and flashing vertical lines at regular intervals. 

Strangely though, the flickering happens in some situations and not in others. For example, when I hit `CTRL`+`ALT`+`DELETE` the blue menu screen comes on and the flickering stops. Also when I expand the task manager to full screen, there is no flickering. The flickering also tends to happen much more while on certain web pages and application than on others. For example, when Gmail is open in the browser, it flickers a lot. But when on `Google.com`, it doesn't. For this reason, I am quite confident that this is not a hardware issue.

Does anyone have any ideas what could be causing this and how to fix it? Please see a [video demonstration here](https://www.youtube.com/watch?v=J6V3QhstvOg)

Picture
[![Flicker - Flashing Picture Toshiba Screen Laptop](https://i.stack.imgur.com/rmdGM.jpg)](https://i.stack.imgur.com/rmdGM.jpg)