function WinSystem : String;
var
  OSVersion : TOSVersionInfo;
  WinVersion: String;
  OrdHigh   : DWORD;
  OrdLow    : DWORD;
begin 
  OSVersion.dwOSVersionInfoSize := sizeof(OSVersion); 
  GetVersionEx(OSVersion); 
  OrdHigh := (OSVersion.dwBuildNumber shr 24) and $FF; 
  OrdLow := (OSVersion.dwBuildNumber shr 16) and $FF; 
  
  if OSVersion.dwPlatformId=VER_PLATFORM_WIN32_NT then 
  begin 
    if (OrdHigh>=5) then 
    begin 
      WinVersion := 'Windows 2000' 
    end 
    else 
    begin 
      WinVersion := 'Windows NT' 
    end; 
  end; 
  if OSVersion.dwPlatformId=VER_PLATFORM_WIN32_WINDOWS then 
  begin 
    if (OrdLow>=90) or (OrdHigh>=5) then 
    begin 
      WinVersion := 'Windows Millennium' 
    end; 
    if (OrdLow>=10) and (OrdLow<90) then 
    begin 
      WinVersion := 'Windows 98' 
    end; 
    if (OrdLow<10) then 
    begin 
      WinVersion := 'Windows 95' 
    end; 
    if (OrdLow<5) then
    begin 
      WinVersion := 'Windows 3.1/ WfWg' 
    end;   
  end; 
  
  Result := WinVersion;
end;