Hello! I seem to have the most annoying problem with my Macbook Pro and I've decided to post her as a "second last" resort before bringing my laptop in. I really hope being able to fix this problem myself though, as I really can't be asked missing my laptop for 2 weeks. (And I'm not going to spend 60-100 euros for a replacement) On a sidenote: thankfully, my laptop is still under guarantee so I won't be charged anything. My MBP is the top-of-the-line 15" model of late 2011 (the 2100 euro one). I already brought it in once around January 2012 due to a hard drive failure. Other than that, my laptop has always been in top-condition, never been dropped once, or never even had the slightest bump. (I treat it with utmost care!) After my HDD got replaced, I reinstalled OSX, but decided to pretty much exclusively use my MBP under Bootcamp. So my OSX is a completely clean install and I only really installed it in the case I needed it for school purposes (which hasn't been the case). I installed Windows 7 (enterprise I think, not sure) and as I said pretty much exclusively booted under windows 7 the past 6 months orso, though I never had any problems playing videogames. (I could play every game on highest/ultra settings, MBPs are beast at gaming apparently ) But now on to the actual problem: Starting from last week (or 2 weeks ago, can't remember), my laptop always started going into sleep mode whenever I would play videogames after 5 to 10 minutes orso. Note that I am always able to immediatly wake my pc up again by pressing the power button, it doesn't even disconnect from Ventrilo or online games. -So it's definitely in sleep mode and doesn't shut down completely- Though unless I close the game straight away, it will go back to sleep mode after a minute orso. At first, it only went to sleep playing Bioshock or Starcraft 2 and other games worked fine. But more recently (the past few days) it has been going to sleep even during the "lighter" games such as League of Legends (on lowest settings) and even Guild Wars (on lowest setting). Going by from all of this, the most obvious conclusion would be that this is a heating problem, and my laptop most certainly becomes hot when playing these videogames, though my fans seem to be working OK. I have already installed lubbo's and cranked up my fans to max RPM. What's weird is that I never before had any issues with overheating, and I have been playing Starcraft 2, Bioshock 1 and 2, League of Legends and Guild Wars 2 (beta) all on highest settings for about a year now -half a year under bootcamp- and never had any issues. This makes me actually doubt wether it's actually heat/fan (Read: hardware) related or not, as my fans (clearly) have always been working correctly. Maybe the hot weather of recent weeks is what's causing this, but I might just be grasping at straws here... My laptop always rests on a flat wooden desk and there's plenty of ventilation room around. (As I said, never had any heat issues before) Usually the room temperature would be around 17-20 degrees, but the past 2 weeks orso we've experienced a bit of a heatwave in Belgium cranking temps up to an average of around 25 with peaks of 30 degrees the past few days. (I suspect my room to become about 35 degrees) So maybe those extra 10 degrees is what's pushing my MBP over the limit? What's weird though is that it seems to be degenerating, as right now I can't even play Guild Wars 1 on highest settings without it going to sleep mode after about a minute of 5. Yet I've also managed to play Bioshock 1 for 2 hours straight yesterday during the day (hottest point) on lowest settings. (Which is still much more intensive than Guild Wars 1 on highest) So for it to be hardware related, it just seems too "random"... I'm completely lost on this one, and it probably is going to end up being heat related, but I'm completely mind-boggled by the "randomness" of it going into sleep mode (sometimes it can handle hourse of intensive work and other times it goes to sleep mode after 5 minutes of what should be an extremely "light" game). I already went to the mac store and they were completely lost too (they checked some settings under MacOS and everything seemed fine), but they too were saying it was running way too hot, even under macOS. I decided not to send it to repair just yet because right now is a very unconvenient time for me to loose my MBP for 10-14 days. Any ideas suggestions please? Thanks for taking the time to read my lengthy post!