Hi guys, I got my 5K since wednesday. I was installing it ( clean install ) and it freezed completely. The machine was only 5 minutes out of the box. Now 4 days later, I want to startup my machine from sleep mode, and I just get a black screen,I could only move my mouse and caps lock light was working. Is this a yosemite issue or an issue with the 5K? I still have 1 week to bring it back and ask my money back.what to do?