Fixing " \windows\system32\config\system is corrupt or missing "

when you start the system, you find " windows cannot start, the following file is missing or corrupt  \windows\system32\config\system ". This message occurs because when your registry gets corrupted or gets errors. For this, you need not format and  reinstall the operating system, since it can be fixed by replacing the system file using your windows boot-able CD. Follow the steps below
Firstly, insert your windows bootable cd  and boot from it .

when a screen with three option appears infront of you. First one for installing windows, second for repairing the windows and at last for exiting.
You just select the second option ie, repairing by pressing the appropriate key it says.

It may ask password, enter the password if you have set, otherwise just press enter.
Press the appropriate number it says for the C drive location where u want to enter
Now, you may enter the directory where u have to repair the system file ie  \windows\system32\config. Type the command below to enter
cd \windows\system32\config

in the above directory which one is corrupted, depending on it type the command
ren software software.bak
or
ren system system.bak
Now you have to copy the files whichever is corrupted ie,
copy \windows\repair\system
or
copy \windows\repair\software

Atlast type exit
For the video based on this post, you may visit http://youtu.be/90XlZdaS0-Q