Repair missing or corrupt files in Windows 7

I  will describe this problem and gives the sollution with SYSTEM FILE CHECKER(SFC) TOOL .
  The System File Checker tool (SFC.exe) scans for missing or corrupted system files and repairs them.
  This is commond Prompt line system,I will show you how to solve this problem using Command Prompt

First of all,When there is missing or corrupt file from your computer there are mainly two problems
A)With missing or corrupt file file,The computer is not going to startup from boot manu,
          then question arrises that how to open Command Prompt?
You have to click this
 HOW TO OPEN COMMAND PROMPT BY WINDOWS 7 SETUP DVD or SYSTEM RECOVERY OPTION?

After watching this post,you can open command prompt.

B)When computer is going to start Normally with file missing or corrupt file
  Open The commomd Prompt --click on Windows/Search/Type"cmd"/Right click on  it and Run as Administration

After opening the Command Prompt

For sollution of STEP A When your computer not going to boot
  You have to type following command in command prompt
      " sfc/scannow/offbootdir=c:\/offwindir=c:\windows"
I have booted windows 7 on "c" drive so write c:\windows
From use of this code It will scan the the folder and fix missing or corrupt files.

sollution of STEP B
                                           When Your computer starts normally

after run the Command Prompt as administration
Type            "sfc/scannow"

The sfc /scannow command scans all protected system files and replaces incorrect versions with correct Microsoft versions.
If any corrupt files are found, they are repaired automatically and a log file is created, It will be located on: C:\Windows\Logs\CBS\CBS.log.

I hope this Tutorial will guide you to solve the problem with missing file.