I installed the NVIDIA GeForce Notebook Graphics Driver 304.48 Beta update last night and this morning my living-room PC looked like this in the browser:

Little colored blocks, flickering lines, sometimes a whole strip of the screen goes green for a moment. It doesn't crash, it just looks horrible. My stomach dropped because artifacts usually mean dying hardware, right? But it's suspicious that it started exactly after the update. How do I tell which one it is without spending money?