I'm getting this same problem, except that the logo flashes for a moment when opening. Running Windows 8; un-installed + installed latest Java JRE, running as administrator, rebooted computer, and run in compatibility mode for windows 7 for no success. I'm using the windows launcher; I some "cisco net security" is telling me that the latest builds have malware and won't let me download, so I haven't re-installed the launcher itself. I also tried using the Linux version which WILL download, but after opening, selecting a mod pack and running, I just get vanilla minecraft.