I can't tell you how many boot records I've blown up over the years. GRUB, NTLDR, and now BCD are enough to turn your brain into ski wax.
Ran into this error trying to get into my Windows 7 Home after I installed Linux Mint on a second drive. It was obviously an artifact from prior XP / XP_x64 / Linux installs and dual boots I had set up, where I had mismanaged placement of the boot records
across different disks.
In order to fix, I used the sharpest Occam's Razor I could find (a must in every tinkerer's toolkit) and disconnected the 2 other hard drives (Mint & NTFS data), insured no externals were plugged in, leaving only the Win7 HD and CD. Booted from my installation
CD, selecting my language, and clicked the repair link. It didn't see my Win7 in the little box in the backgrounds while it ran, but it sounded like it stuck something on the HD.
Rebooted, same error, back to CD, clicked again on the Repair link. Aha! This time it sees my install in the little background box.
Rebooted again, this time to an install and diagnostic screen originating from the HD (no NTLDR error). Ran the installation from that screen, again selecting Repair. Again it saw my Win7, and asked to reboot.
Rebooted again, this time into the F8 switch which was recommended above. I selected Start Normally, and it started fine. Rebooted, and am no longer running into the NTLDR error. Plugged in my other two HDs, and I have my data and Linux drives ready to
go and accessible from the secondary BIOS-level boot disk screen.
Fixing MBRs are an interesting exercise but can be a huge time sink, especially if you've bolluxed up the works by playing with different OS and their boot setups. Sure, it's nice having Linux show up on your Windows boot option screen, and vice-versa in
GRUB. But....
If your machine has at least BIOS level boot drive choices, UNPLUG ALL YOUR OTHER DISKS before installing Windows or Linux. Then plug them back in and use the BIOS or secondary level boot selectors to get into the OS you want. Best. Advice. Ever.