On the computer I'm working on, after a few hours of Word and web pages, there are horizontal blurry lines randomly appearing on the screen. They go the whole way from left to right, and the gravity of the problem depends on the content being displayed, for instance on this page where I am typing there is no line, nor on the desktop, but on the main page of the forum there are a lot, it gets hard to read.
The screen is a cicero 17" CRT and the video card is a geForce MX400 or something like that.
Could it the graphic card?
Get a can of compressed air and spray your monitor out as good as you can. Spray out dust from all the openings you can see as good as you can. Spray out your case too.