Hey guys, I disassembled my sister's 13 inch unibody 2011 MBP because she was complaining about really loud fan noise. I checked the temps and found that the CPU was running at 80-88 C so I cleaned the dust buildup and did a re-paste on the CPU and chipsets. After having re-assembled the computer, I noticed this problem. I can boot from the OS disk and command-r works too but for some odd reason I just cant boot into the OS anymore. I doubt it has anything to do with any hardware as I have made sure to have everything in place and installed correctly TWICE. What could be causing this to happen? My sister is going to kill me if I don't find a solution soon Thanks!