Hi everyone, First, thank you to anyone who can help me with this! I have been googling like crazy and the only information I can find on my issue actually came from this very forum. Please see this thread. That is my exact issue. It randomly started happening about a week ago, and its driving me mad. It only appears on certain backgrounds and the placement of the lines is not typically the same. I noticed the thread above did not have a resolution so I am hoping someone out there has since discovered a way to solve this. I bought my machine refurbished in 2011 and it has been working great, up until this problem. It's something that I can live with, but I do a lot of graphic design work in photoshop and it is bothersome when I'm working on images. I do not have Apple Care and am currently on a tight budget, so hoping for an inexpensive fix. Please, can anyone out there help me with this? Thank you!