How to Fix Display Issues and Hard Drive Errors on MacBook Pro (Model 10,1)?

It sounds like you're dealing with a significant issue related to your MacBook Pro, specifically with the display. The presence of a horizontal grey band at the bottom of your screen and the "Graphics error" message suggests that this is likely not a software problem. Instead, it could indicate a hardware failure, possibly related to the graphics card or the connection to the display. Given that this started after a recent update to Yosemite, it's understandable to feel frustrated, especially since there have been reports of graphic card failures in the 2011 and 2012 MacBook models. While Apple hasn't officially acknowledged these issues, many users have experienced similar symptoms. It’s worth noting that even if you revert back to Mavericks, the problem may still persist, as some users have found. Your best course of action is to take your MacBook to an authorized repair center for a thorough diagnosis. They can assess whether the issue is with the graphics card, the display itself, or possibly a connection problem. If you haven't purchased an extended warranty, you might need to cover the repair costs, but it's worth getting a professional opinion first. If you feel strongly about the issue being a known defect, you might consider bringing this up with Apple. Sometimes, if you insist that it’s a recognized problem, they may offer repairs at no cost, especially if they have internal guidelines for handling such cases. This approach has worked for others in the past, so it could be worth a try. Ultimately, getting a professional diagnosis will help clarify the situation and guide you on the next steps.