How to set the hide extension for known file type in Windows 7

Step 1:- First Open My Computer
Step 2:- Open any Drive
Step 3:- Pres Alt+T
Step 4:- Menu Bar will activate
Step 5:- Select Tools Menu
Step 6:- Click on Folder Option
Step 7:- Select View Tab
Step 8:- Uncheck the hide extension for known file types.
Step 9:- Click on Apply Button
Step 10:- Now click on Ok Button. Now setting will apply.