What Is a THEMEPACK File?
A file with the THEMEPACKfile extensionis a Windows theme pack file.
However, you may want to convert a .THEMEPACK file to a .THEME file.

you might do that with the freeWin7 Theme Converter.
After you load the file into that program, place a check onThemeoutput typeand then selectConvert.
This will let you copy out the wallpapers, audio files, and anything else you want to use.

The background images in a .DESKTHEMEPACK file are stored in theDesktopBackgroundfolder.
Still Can’t Open It?
But in reality, they could just be compressedJARfiles, something the programPack200is responsible for.
THEME files, then, justreferencethose items that are stored elsewhere.
You candownload free THEMEPACK and DESKTHEMEPACK files directly from Microsoft.
FAQ
Go toWindows tweaks>Apps, scroll down, pick the theme, and clickUninstall.
Right-click a blank area of the desktop, selectPersonalize, and go toThemes.
Select a background, accent color, Windows sound, and mouse cursor.
Click theSave themebutton, enter a name for the theme, and clickSave.
you’re free to only export custom themes.
Right-click a blank area of the desktop, selectPersonalize, and go toThemes.