function WMPOpenCount: Integer;
var
  WMPNum: TArrayOfString;
  WMPExt: string;
  I: Integer;
begin
  Result := 0;
  if RegGetValueNames(HKLM, PlayerExts + 'Types', WMPNum) then
    for I := 0 to GetArrayLength(WMPNum)-1 do
      if RegQueryStringValue(HKLM, PlayerExts + 'Types', WMPNum[I], WMPExt) then
        Result := Result + Length(WMPExt) + 1;
end;