hello, This is my first post to this forum so i hope i posted it in the right section. I'm going to work on a camping for the next 6 weeks, including tasks like: making a promotional video, creating cycling maps and many more things I will need my macbook with. My macbook is a 2009 model with the optical drive replaced by a second harddrive (samsung ssd evo 120gb) and "programmed" to a fusion drive through some simple lines in terminal. Yesterday (the third day of my workvacation -_-") i started my macbook and the apple logo showed up, I am not sure if the grey bar appeared. After a few seconds a lot of text appeard over the screen (still showing the apple logo) the text was like when you start in single user mode. A few seconds later some sort of official apple error was shows for like a second(could not read the entire thing) and the macbook shuts down. I restarted it and it looked like it would start normally but after the loading screen appeared and the bar beneath the apple logo was filled for like 30 percent it shuts down. I tried booting it up holding the alt key, i clicked windows instead of mac os and it started without a problem. But I needed the programs installed on my mac os so i tried fixing the problem. I tried starting in single user mode because one website told me to and type the line "fsck -fy" but it says "invalid node structures". So an other website told me i needed to go to the mac recovery screen, but holding CMD + R does not work neither holding alt while booting because only a windows drive icon and a Macintosh drive incon wil appear (sometimes two Macintosh drive icons for some reason????). I can replace a macbook optical drive or boot into terminal and use some simple lines but I am far from pro. Can somebody help me with this problem, you will help me alot! Btw: the internet over here is very slow, i ried downloading diskwarrior already but that was hopeless. A friend of mine has brought his macbook pro so maybe that will come in handy.