Show file extension in window Vista?

Question

Open Control Panel >>> Folder Options, View tag , clear check box "Hide extensions for known file types", click OK.

I cann't show file extension?????????
I don't know why????????
My account is administrator, my computer don't have virus.

Answer 1

Clearing the check box is the correct thing to do. Have not heard of this problem before. Try it again and make sure you do the step 4.

In Control Panel:
1. Double-click Folder Options
2. Click the View Tab
3. Uncheck Hide Extensions for Known File Types
4. Click Apply button (at the bottom of the window)
5. Click OK

Simply clicking OK should work, however, I would try the Apply button also since you seem to be having a problem.