Windows 8 and 7 - Show file extensions

If you can't see file extensions in explorer, here's the answer:

Windows 8.x

Start File Explorer (right click Start and click File Explorer)

Click the View tab

Click File Extensions - see the example below:

Windows 7
Start Windows Explorer (double click My Computer)
Click Organize
Click Folder and search options
Click the View tab (Folder Options window)
Click to disable (remove the tick) from 'Hide extensions for known file types' - as below:

Also in Control Panel

For both Windows 7 and 8 you can find Folder Options in Control Panel. Open Control Panel and search for "folder options" - you'll see the above window (Windows 7 or 8, it is the same from Control Panel).

Reference

http://windows.microsoft.com/en-us/windows/show-hide-file-name-extensions#show-hide-file-name-extensions=windows-7