MacBook pro won't load after apple logo. Possible GPU issue

I've got an early 2011 15" Macbook pro running Yosemite. Few weeks ago, when I turned it on, it didn't proceed to load after the apple logo. I've looked up for solutions on apple support community for similar issues and as they suggested, I've done all the PRAM and SMC resets. But no luck. Then I opened up the bootcamp partition thinking that it would work. But it's still the same deal, but this time I've got bit more info on the error. On windows boot up, I've got a blue screen with the error message "attempting to reset display drivers and recover from timeout failed". I then booted up windows safe mode and updated the AMD graphic driver. No luck. Then I disabled it and let the computer run on Intel graphics. On windows, it works but with stretched out graphics and Mac is still the same. I guess what's on windows won't affect the Mac partition. So I'm thinking that this is actually a hardware issue, but again, I'm not entirely sure.

Therefore, I'd like to get your opinion on how to go about fixing this issue,

Thank you