Lcd tv picture problem. I have a Olevia LCD HDTV, 26" a little over 2 years old and out of

Question

I have a Olevia LCD HDTV, 26" a little over 2 years old and out of warranty of course. When you first turn it on it's perfect, but after it's been on for 30 minutes or so it gets a horizontal thin black line a few inches down from the top. I'm sure this is nothing I can fix, but was really wondering if any one knew if it was fixable by a repair shop and whether it was going to be an expensive fix. Thanks.