Saunnie wrote: If You’re in windows you can rename a file with these steps:
1. Open the explorer window where your files exist
2. Select the Tools >> Folder Options menu item
3. Click the View Tab
4. Uncheck the option to “Hide extensions for known file types”
5. Click “apply to All Folders if you always want to see the file extensions for every file no matter what folder you are in
6. Click ok to accept all changes and close the dialog window
7. You should now see all the file extensions of the files in the current folder
8. Right click on a filename you wish to change and select Rename
9. Rename the file extension to anything you’d like.

Once you’ve done this, you can just right click a file and rename it in seconds. No software required!