I had a MacBookPro with Snow Leopard and Bootcamp with Windows 7 all working well. In order to blow some more life into MBP I replaced my DVD drive with a SSD. Reinstalled Snow Leopard. And then when I get a hold of a Windows 7 iso image decided to move Windows to SSD. I partioned the drive using Disk Utility. And installed Windows 7 using a USB Stick and rEFIt.
At the end of the process I was able to boot into the new Windows 7. Later I decided to get rid of the old boocamp partition and notoced that it was not bootable. I did not care about it and went ahead and deleted the bootcamp partition using Bootcamp Assistant.
However this process rendered the new installation unbootable, So I went ahead and tried a few installations by partioning with bootcamp assistant and disk utility. However no matter what i tried I am getting the black screen "Missing Opeating system" message. It boots fine with Parallels.
My guess is previously the boot information was on the first bootcamp partition and somehow it was pointing to the second partition.
In the meanwhile rEFIt displays 2 macOS volumes (correct) 1 unknown volume(no idea) 1 Windows Volume (correct) for the internal disks and two windows volumes for my USB installer volume. So I am a bit confused about the extra internal unknown and external windows volumes. So I am bit confused about that too.