Monitor problem

I'm a bit new to the whole computer fixing thing so I need a bit of help. My mom just got a new monitor because she was having trouble with the old one. Naturally, I wanted to figure out what was wrong and possibly fix it instead of throwing it out. So I hooked it up and found that from time to time it gives off blurry/smeary lines horizontally across the entire screen. So I have a few questions: 1) what is the problem? 2) is it fixable and how? 3) if I can't fix it, is there anything I can do with it or should I just throw it out?  Thanks

If it's new, why don't you make a get a refund as you return to the manufacturer?

Its a few years old so the warranty has expired