I got a macbook pro 13inchs (2011), Yosemite. One week ago a folder with a sign question appeared in the first screen and that's where all my problems started. I follow some links in order to reinstall the operating system but seemed like there wasn't disk on the macbook. I did two things:
I bought a new disk and I installed it.
Then I performed a diagnostic test in order to check if there was a hardware problem: no problems.
However, I tried once more to reinstall the operating system but again seemed like there was no disk in the macbook. I don't know what do from this point since the results from diagnostic test (exhaustive one) showed no hardware problem at all. Pls, help me