When I turn my Imac, it goes from the white screen to a black screen, then blue and then desktop. The whole process is fast, but is not normal. (at least is not like my previous MBP or the videos that I have seen on youtube) At the black screen stage, I can see some boot up information, etc, It is fast so I am not able to read it all. It looks like when booting an old windows or dos machine How can I change this? Is this normal? It also shows the screen when I shut down.