Here are the steps that worked for me:
- First, boot from Windows 7 installation (DVD).
- On a MacBook Pro (with BootCamp), power-on with Alt/Option key held down.
- Initially, only the standard Mac and Windows options appear, but wait a few more seconds and then additional options appear for Windows and EFS methods of booting from the DVD.
- I selected the Windows option (guesswork).
- On a MacBook Pro (with BootCamp), power-on with Alt/Option key held down.
- Select the System Recovery option http://www.sevenforums.com/tutorials/668-system-recovery-options.html
- Select the STartup Repair option http://www.sevenforums.com/tutorials/681-startup-repair.html
As it happened, this whole process was a distraction. I was trying to get a BootCamp-W7 Virtual Machine (VM) in Parallels working – it would boot OK in BootCamp but not Parallels. It was a matter of identifying the problem by excluding other possibilities, as much as hoping for this to be the fix. However I record the process I went through, here, for posterity.