My system had an odd problem that took me a while to track down, so I'm posting it here.
I need to boot in to safe mode, but when I did msconfig, boot tab, no os was listed and I couldn't click safe boot (or any tick box for that matter). Likewise in Control Panel -> System and Security -> System -> Advanced System Settings, Start and Recovery, there was no default os. I tried opening cmd and running bcdedit /enum, that didn't work either, said no file. Eventually booted Windows 7 cd to get into win7re cmd prompt and tried again with bootrec /RebuildBcd, found 0 operating systems, same with /ScanOS.
The cause of the problem is installing Windows 7 on a bare drive. There is a 100MB reserved drive created and this is the active drive and has c:\boot directory. I went into control panel, disk management and gave this 100mB drive a letter so I could access it. Then I copied the \boot directory to c:\ plus boot.bcd* files, bootmgr and EUMONBMP.SYS (just to be sure). I then made c: the active drive and straight away msconfig boot tab has the os and tickable boxes, etc..
For what I read this might also be the solution for my hibernate problem too, but that's something to try another day.