Earlier versions of Microsoft Windows may use desktop theme files with a .the or .thm file name extension. Desktop theme files in Windows 2000 must have a .theme file name extension. Renaming .the or .thm files to .theme files allows you to use the older desktop theme files in the Desktop Themes dialog box in Windows 2000.
NOTE: Although an older theme file may be recognized by the Desktop Themes dialog box in Windows 2000, there may still be compatibility issues. See the "More Information" section of this article for additional information.
To change a .the or .thm file extension to .theme in Windows Explorer:
Right-click a .the or .thm file, and then click Rename.
Change the extension from .the or .thm to .theme, and then press ENTER.
Note that you can also rename files by using the rename command at a command prompt.
After a theme file has a .theme extension, you can use the theme file as described in the following article in the Microsoft Knowledge Base:
257841 How to Configure Desktop Themes in Windows 2000
Note that some themes are not displayed properly in Windows 2000 without extensive changes to the .theme file. Many desktop themes rely on the %THEMESDIR% environment variable. By default, this environment variable is not set to any value in Windows 2000. Most newer desktop themes can find the location for the files associated with the theme, but some older themes (such as those included with Microsoft Plus! for Windows 95) require that you either edit the theme file or add a %THEMESDIR% environment variable.
Note that the addition of the %THEMESDIR% environment variable does not necessarily make all themes work correctly. Many themes assume a certain folder structure that involves %THEMESDIR% subfolders. To determine the exact structure that the theme expects, open the theme file in a text editor such as Notepad.