Why is Windows 7 not listed in "Start-up and Recovery" Options

Solution 1:

I'm speculating, but the fact Windows doesn't read anything, but still boots, could mean the Windows bootloader is somehow damaged or has been replaced? Any chance of a virus infection or damage?

You could try using something like EasyBCD (Info) and see what that thinks.

When I had my PC setup for Vista/Win7 dual boot and destroyed the Vista partition, my machine completely failed to boot because the Vista partition was the primary (and so I'd trashed all the bootloader, etc along with the partition - it was a bit of a facepalm moment...). Anyway, simply booting to my Win7 disk and using the StartUp Repair option did the job - it rebuilt everything that was needed on the Win7 partition. Might be worth a try.

Or, if you prefer to do things yourself rather than using a magic button, there's apparently a tool available in the recovery console to the same effect - see http://support.microsoft.com/kb/927392/