Windows 7 not booting. grub bash shell appears

Question

My Windows 7 x64 desktop PC stopped booting after I restarted it.

This message appears:

drive 0x80(LBA): C/H/S=1023/255/63, Sector Count/Size=16434495/512
    Partition num: 0, active,   Filesystem type is ntfs, partition type 0x07

****

Options if your HDD is larger than 1TB:
* Move your boot files to a smaller partition at the start of the HDD.
* Format the HDD and allow Windows 7 to create a 100MB boot partition.
* Shrink and move your partitions with GParted.

Press any key to read more...

Then another screen suggesting some options appears, and then a Minimal BASH-like shell appears like:

grub> _

I have no idea what could have happened. I don't even remember using grub to install Windows 7. Pretty sure I used the same installer to format my OCZ Vertex 2 90GB to NTFS and install Windows there. No partitions. Then I have a 2TB WD HDD with one partition as storage, no OS installed there.

Is there a way I can restore the MBR boot? I'd prefer not to have to reinstall the whole OS again.

UPDATE Just in case it has something to do with this, I restarted after I shrinked the pagefile a little bit in my SSD (I have 16GB RAM).

Solution

Ok, I've managed to solve the problem. These are the steps:

1. Boot from a Windows 7 DVD and select "Repair your computer..."
2. In the System Recovery Options screen select "Command Prompt"

3. Type in the following commands:

   bootrec.exe /FixMbr
   
   bootrec.exe /FixBoot
   

Source: http://www.tomshardware.com/news/win7-windows-7-mbr,10036.html

Comments

[galacticninja]

I had the exact same issue, in my case, it was because I was defragmented my HDD using PerfectDisk. It must have modified the MBR somehow.