I am a novice user of Ubuntu. I had Ubuntu 12.04 LTS and Windows 8 dual operating system side-by-side before in two separate Hard drive (one SSD and other HDD). But My Windows crashed and I decided to install Windows 8.1 .So when I installed Windows 8.1, the boot menu I used to choose operating system did not appear and it directly logged into Windows 8.1. Then I tried to install Ubuntu 12.04 LTS again with USB stick with the procedure given here:
But It didn't work. It gave me error "missing operating system" when I tried to boot my USB from UEFI boot menu and then it directed to a boot menu where I could choose my old Ubuntu (but not my new Windows 8.1). To fix this error I decided to install a fresh copy of Ubuntu and so I formatted that drive using Windows. Now, when I try to boot my USB drive, it gives me the same error "missing operating system" with some bonus errors "unknows file system" and the a command prompt with "grum rescue >" appear.
I am really stuck with this problem. Need help