For saving your computer from this error you have to first boot with Windows 7 DVD.
Insert Windows 7 DVD before Windows Logo Appears.
When Prompted with " Press any key to boot from cd" ; Press any key
After the files load, select the language then select "Repair Your Computer".
The Repair Environment will detect earlier installations of Windows 7.
Select the Installation you want to repair and select ok.
This will sort out any file errors and you should be ok.