I just installed my new computer (Gainward Z87X-UD4H, i7-4770, no video card). Due to some gaming, I installed Windows 7 first. Afterwards I installed Ubuntu 12.04 LTS. Now, my Ubuntu starts without any problems. Choosing Windows in grub, it hangs on grub's purple screen.
Again, this is not about a purple screen for Linux (for example, My computer boots to a black screen, what options do I have to fix it?), it's more related to this, this or this. How I can debug/fix that?
For the protocol, I tried: