The game begins with a black screen and a popup from Steam at the bottom right corner of the screen (The images of the sponsors at the beginning of the game does not appear because the screen is black), the popup of Steam never disappears (the popup of Steam disappear only when the FM15 goes normally to the main menu of the game - see step 3).
Then goes normally to the main menu of the game.
Please see my thread in SI forum.
The SI says that Avast is causing this problem in the game (Football Manager 2015) (Please see the video on YouTube to see the problem in video).
Answer to the first question: No, I have only Avast Free Antivirus.
Answer to the second question: A few days ago I did format my computer to see if this solves the problem (unfortunately the problem was still there) and the Avast was the first and only Antivirus I installed to my pc.