os x yosemite sleep issue
after os x yosemite installation my macbook pro never sleep and awake. when i close the lid or press sleep from apple button, screen was black and macbook never sleep and the screen was not wake up again. always i have to do restart with power button. I read all articles on apple support discussions and i did try many ways to fix it like SMC&PRAM restart, delete some of applications, change, power settings also i upgraded my RAM to 16gb but they could not fix my problem. please help me about this issue. my macbook informations are as below.
MacBook Pro (15-inch, Early 2011)
2 GHz Intel Core i7
16 GB 1333 MHz DDR3
Intel HD Graphics 3000 512 MB
MacBook Pro, OS X Yosemite (10.10.2)