Оформил: DeeCo
Автор: http://www.swissdelphicenter.ch

uses ComObj, SyncObjs;

 var
   GetCurrentThemeName: function (pszThemeFileName: LPWSTR; cchMaxNameChars: Integer;
     pszColorBuff: LPWSTR; cchMaxColorChars: Integer; pszSizeBuff: LPWSTR;
     cchMaxSizeChars: Integer): HRESULT; stdcall;

 procedure TForm1.Button1Click(Sender: TObject);
 var
   FileName, ColorScheme, SizeName: WideString;
   hThemeLib: THandle;
 begin
   try
     hThemeLib := LoadLibrary('uxtheme.dll');
     if hThemeLib > 0 then
       GetCurrentThemeName := GetProcAddress(hThemeLib, 'GetCurrentThemeName');
     if Assigned(GetCurrentThemeName) then
     begin
       SetLength(FileName, 255);
       SetLength(ColorScheme, 255);
       SetLength(SizeName, 255);
       OleCheck(GetCurrentThemeName(PWideChar(FileName), 255,
         PWideChar(ColorScheme), 255, PWideChar(SizeName), 255));
       // show the the theme path and file name. 
      ShowMessage(PWideChar(FileName));
       // show the color scheme name 
      ShowMessage(PWideChar(ColorScheme));
       // show the size name 
      ShowMessage(PWideChar(SizeName));
     end;
   finally
     FreeLibrary(hThemeLib);
   end;
 end;