How to display file extensions in Windows 7 system

Sometimes, looking at some files, because there is no extension, we use the wrong software to open, the file itself if the default to open the file, it is likely to make the file invalid. Is there a way to directly display file extensions? Here's how to do it:

Step 1: In "Start”, click “Control Panel”.

Step 2: In the "Control Panel>, select "Appearance & Personalization".

Step 3: In "Appearance and Personalization", select “Folder Options”.

Step 4: Enter the “View" option bar in the “Folder Options”

Step 5: Use the mouse to pull the slider down, find “ hide the extension of the known file type ”, remove the checkmark in front of it, and click OK, you can see The hidden extension to each file.