I've tried to install windows 7 several times now and have erased the drive at least 2-3 times. I keep getting an issue booting the 2nd or 3rd time after I install the OS, with the computer hanging after POST saying boot mgr missing. I've tried to repair the partition, erase the partition etc but to no avail. Once I finish installing Windows after an erase, it boots for 2-3 times, then I update or take the dvd out and it seems to have the same issue.
The system I think is getting confused by the drive ordering as there are 7 hard drives in this system. It is set correctly in the bios boot manager, but I still get this issue. I feel like it happens when I remove the windows 7 dvd, but can't say with certainty that every time that occurs i can no longer boot into the OS.
That's what I do when I install a windows OS. This ensures the boot loader and OS are on the same drive, otherwise windows will try to put the boot loader on a seperate drive. Later if that drive fails or is removed, you will get the boot manager missing error even though the OS drive is fine.