Windows includes a utility that scans your Windows 7 system for corrupt, changed or missing system files. Normally you run this utility in booting off the DVD into repair mode but running this from the command prompt is much easier.To run this utility , you will need to open a command prompt in administrator mode and follow the steps.
- Go to Start menu.
- Select All Programs and then Accessories
- Right-click on Command Prompt and select Run As Administrator.You can run the service in Command Prompt, by using the following syntax: SFC [/SCANNOW] [/VERIFYONLY] [/SCANFILE=] [/VERIFYFILE=] [/OFFWINDIR= /OFFBOOTDIR=]
- Press Enter
This will scan and attempt to repair any files that are changed or corrupted. You can run that command with sfc /scannow.