Hi, I have a mid-2012 13 inch macbook pro, bought from new about a year and a half ago. I'm having this problem where occasionally my screen will freeze and become kinda pixelated with lots of diagonal lines... There's also this rhythmic ticking/clicking sound. I can't see my cursor and can't click anything or bring up task manager and have to force shut down by holding the off button. Then I start it up again and everything is fine for a while. This happens a lot when I am gaming for some reason, but has happened once when just streaming videos. It has just been happening the past couple of days, I had Mavericks but have just updated to Yosemite and it has happened again. I have read similar cases online where it freezes and theres noises coming from the hdd, however my noises are not from the hdd. I had headphones on the first time and the noise came from the headhones and scared the **** out of me. I've only ever had one real issue with my macbook where I had to get some cable inside which connects the hard drive to everything else replaced cause it could not recognise the hdd. Since then I've had no problems with it If anyone has any ideas it would be greatly appreciated. Thanks!