Frozen loading screen

So basically when I bring up Minecraft the loading will freeze. The only way to fix it is by redownloading Minecraft. I think I might know why this problem is happening. It could be because I have the disc version. I saw something once when I started up Minecraft saying that the bug was fixed. But it is still doing it, so it might be that I have the disc version. But if you could please find the problem it would be greatly appreciated.