I've been having weird this issue and i just reformatted my computer. The sleep light is pulsating but display just brightens and freezes until i move/touch it goes back to normal. And when i put the computer to sleep i hear the hd and fan coming back on but screen does not turn on. I Googled everywhere i didn't find anyone else with this issue. I have had this problem before i reformatted but it some how fixed itself, i'm not even sure what i did. I tried resetting the PRAM and SMC.... no luck there. Any suggestions?