Hey there, I've got a MacBook Pro 15" from Beginning 2011. Since a few weeks it freezes on startup (white screen with apple logo and progress bar on 60%) I've tried PRAM/NVRAM, SMC, Apple hardware check(no failures), and I switched the RAM-modules vice verca, even a new hard disk cable. Nothing helped. Then I installed a small SSD for testing and installed HighSierra. After that everything seemed to work fine, I restartet about 30 times, without problems. So I thought it is the hard disk. I bought a new 500GB SSD and installed HighSierra again. All seemed fine so far. Yesterday I installed the newest updates. After that my MBP froze and showed me a completely red picture when I wanted to start the photos-app. Now the MBP is not starting again. After the white screen with apple logo and progress bar(60%) the picture turns black and all fans are running on 100%. Does anybody have any ideas?