To stop Windows from hiding filename extensions, do the following:
Windows Vista and Windows 7Edit
- Open Folder Options by clicking the Start button, clicking Control Panel, clicking Appearance and Personalization, and then clicking Folder Options.
- Click the View tab, and then, under Advanced settings, clear the Hide extensions for known file types check box, and then click OK.
Open Windows Explorer (Start > My Computer) or click Control Panel, then Appearance and Themes.
Choose Tools > Folder options...
Click the View tab.
Uncheck "Hide extensions for known file types" and click "OK".