I have a 64 bit windows 8 computer that I have been making games on unity 4 for the last couple of years. I decided to upgrade to unity 5 so I could download some assets on the store. So I downloaded unity 5 (64 bit version) and opened it after the long install. I saw the splash screen with the unity logo, but then it was a dark grey, and didn’t continue. I have reinstalled it, twice already with no luck. If anyone has an answer for this, it would be greatly appreciated!