On my HP laptop with windows 8, I installed Lubuntu as a dual boot from a live CD. At first, I could only access grub through hitting F9-ubuntu, so I tried Boot Repair to no avail. Then I tried manually loading grub's MBR file where Windows' was, but it didn't help. I tried turning off secure boot in the BIOS (UEFI), and it opened GRUB straight away. However, when I try to open the windows option, it flashes black and the same menu comes up, no matter how many times I hit it. When I turn secure boot back on, it repairs Win8 and I can boot into it until I turn it off again.
I have tried fixing grub, fixing the BCD from the Windows side through recovery and through third party apps, and tried every permutation of all this at least once. All I want is for my computer to open grub, give me a choice between Lubuntu and windows, and boot the one I ask for. This is a last ditch effort; I've been working on this about 12 hours straight to no avail. If anybody can help, I would really, really appreciate it! :)