detectar que windows tienes.
 

Si en delphi 7, lle pulsa la paleta about, despues help, te dice que tienes instalado el windows xp con service pack 2.

como hago eso para que me lo detecte o el codigo necesario.?

Hola,

Código Delphi [-]
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 function EsWindows95 : boolean;
 var
   OVI: TOSVersionInfo;
 begin
   Result := false;
   OVI.dwOSVersionInfoSize:=
     SizeOf(TOSVersionInfo);
   if (GetVersionEx(OVI)) then
     Result := (OVI.dwMajorVersion = 4)
       and (OVI.dwMinorVersion = 0);
 end;
 
 { ············································································ }
 
 function EsWindows98 : boolean;
 var
   OVI: TOSVersionInfo;
 begin
   Result := false;
   OVI.dwOSVersionInfoSize:=
     SizeOf(TOSVersionInfo);
   if (GetVersionEx(OVI)) then
   Result := (OVI.dwMajorVersion = 4)
     and (OVI.dwMinorVersion = 10) and
       not (OVI.szCSDVersion[1] = 'A');
 end;
 
 { ············································································ }
 
 function EsWindows98SE : boolean;
 var
   OVI: TOSVersionInfo;
 begin
   Result := false;
   OVI.dwOSVersionInfoSize:=
     SizeOf(TOSVersionInfo);
   if (GetVersionEx(OVI)) then
   Result := (OVI.dwMajorVersion = 4)
     and (OVI.dwMinorVersion = 10) and
       (OVI.szCSDVersion[1] = 'A');
 end;
 
 { ············································································ }
 
 function EsWindowsME : boolean;
 var
   OVI: TOSVersionInfo;
 begin
   Result := false;
   OVI.dwOSVersionInfoSize:=
     SizeOf(TOSVersionInfo);
   if (GetVersionEx(OVI)) then
     Result := (OVI.dwMajorVersion = 4)
       and (OVI.dwMinorVersion = 90);
 end;
 
 { ············································································ }
 
 function EsWindowsNT : boolean;
 var
   OVI: TOSVersionInfo;
 begin
   Result := false;
   OVI.dwOSVersionInfoSize:=
     SizeOf(TOSVersionInfo);
   if (GetVersionEx(OVI)) then
     Result := (OVI.dwMajorVersion < 4);
 end;
 
 { ············································································ }
 
 function EsWindows2000 : boolean;
 var
   OVI: TOSVersionInfo;
 begin
   Result := false;
   OVI.dwOSVersionInfoSize:=
     SizeOf(TOSVersionInfo);
   if (GetVersionEx(OVI)) then
     Result := (OVI.dwMajorVersion = 5)
       and (OVI.dwMinorVersion = 0);
 end;
 
 { ············································································ }
 
 function EsWindowsXp : boolean;
 var
   OVI: TOSVersionInfo;
 begin
   Result := false;
   OVI.dwOSVersionInfoSize:=
     SizeOf(TOSVersionInfo);
   if (GetVersionEx(OVI)) then
     Result := (OVI.dwMajorVersion = 5)
       and (OVI.dwMinorVersion = 1);
 end;
 
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El componente JvComputerInfoEx de la JVCL te permite obtener estas infos y mas..