The following example demonstrates how to detect if your application is running under Windows NT. Note that the code will compile under both 6 and 32 bit platforms. Example: {$IFNDEF WIN32} const WF_WINNT = $4000; {$ENDIF} function IsNT : bool; {$IFDEF WIN32} var osv : TOSVERSIONINFO; {$ENDIF} begin result := true; {$IFDEF WIN32} GetVersionEx(osv); if osv.dwPlatformId = VER_PLATFORM_WIN32_NT then exit; {$ELSE} if ((GetWinFlags and WF_WINNT) = WF_WINNT ) then exit; {$ENDIF} result := false; end; procedure TForm .Button Click(Sender: TObject); begin if IsNt then ShowMessage('Running on NT') else ShowMessage('Not Running on NT'); end;