Essa semana precisei implementar um software de auditoria de hardware e na tela de cadastro de patrimônios, para facilitar o cadastro implementei algumas coisas para serem buscadas do próprio Windows instalado como o serial do Windows,  sua versão, etc; da mesma forma o do Office, então procurando dll, código e pela Net achei uma Unit que já possuia algumas funções para decodificar os serials keys.

UNIT  MSProdKey v2.2

Description: Decodifica e visualiza a Product Key, Product ID e Product Name usado  *
* na instalação do: Windows 2000, XP, Server 2003, Office XP, 2003. *
* *Atualização* Agora trabalha para usuários sem direitos Administrativos *
* Código limpo e alterações comentadas

EXEMPLOS

if not IS_WinVerMin2K then // Se a versão do Windows não é menor que Windows 2000*
Edit1.Text := 'Windows 2000 ou Superior Requerido!' // Mostra essa messagem
else // If the Windows version is at least Windows 2000                          *
Edit1.Text := View_Win_Key; // Mostra o Windows Product Key                      *
Label1.Caption := PN; // View the Windows Product Name                           *
Label2.Caption := PID; // View the Windows Product ID

UNIT

unit uMSProdKey;

{
**************************************************************************************
* Unit MSProdKey v2.2                                                                *
*                                                                                    *
* DESCRIÇÃO: Decodifica e visualiza a Product Key, Product ID e Product Name usado   *
*            na instalação do: Windows 2000, XP, Server 2003, Office XP, 2003.       *
*                                                                                    *
* *Atualização* Agora trabalha para usuários sem direitos Administrativos            *
* Código limpo e alterações comentadas                                               *
*                                                                                    *
*  Modo de Uso: Adicione uMSProdKey na cláusula USES de seu Aplicativo.              *
*                                                                                    *
*  Example 1:                                                                        *
*                                                                                    *
* procedure TForm1.Button1Click(Sender: TObject);                                    *
* begin                                                                              *
*   if not IS_WinVerMin2K then // Se a versão do Windows não é menor que Windows 2000*
*   Edit1.Text := 'Windows 2000 ou Superior Requerido!' // Mostra essa messagem      *
*   else // If the Windows version is at least Windows 2000                          *
*   Edit1.Text := View_Win_Key; // Mostra o Windows Product Key                      *
*   Label1.Caption := PN; // View the Windows Product Name                           *
*   Label2.Caption := PID; // View the Windows Product ID                            *
* end;                                                                               *
*                                                                                    *
*  Example 2:                                                                        *
* procedure TForm1.Button2Click(Sender: TObject);                                    *
* begin                                                                              *
*   if not IS_OXP_Installed then // If Office XP isn't installed                     *
*   Edit1.Text := 'Office XP Required!' // Display this message                      *
*   else // If Office XP is installed                                                *
*   Edit1.Text := View_OXP_Key; // View the Office XP Product Key                    *
*   Label1.Caption := DN; // View the Office XP Product Name                         *
*   Label2.Caption := PID; // View the Office XP Product ID                          *
* end;                                                                               *
*                                                                                    *
*  Example 3:                                                                        *
* procedure TForm1.Button3Click(Sender: TObject);                                    *
* begin                                                                              *
*   if not IS_O2K3_Installed then // If Office 2003 isn't installed                  *
*   Edit1.Text := 'Office 2003 Required!' // Display this message                    *
*   else // If Office 2003 is installed                                              *
*   Edit1.Text := View_O2K3_Key; // View the Office 2003 Product Key                 *
*   Label1.Caption := DN; // View the Office 2003 Product Name                       *
*   Label2.Caption := PID; // View the Office 2003 Product ID                        *
* end;                                                                               *
*                                                                                    *
**************************************************************************************
}

interface

uses Registry, Windows, SysUtils, Classes;

function IS_WinVerMin2K: Boolean; // Check OS for Win 2000 or higher
function View_Win_Key: string; // View the Windows Product Key
function IS_OXP_Installed: Boolean;  // Check if Office XP is installed
function View_OXP_Key: string;  // View the Office XP Product Key
function IS_O2K3_Installed: Boolean; // Check if Office 2003 is installed
function View_O2K3_Key: string; // View the Office 2003 Product Key
function DecodeProductKey(const HexSrc: array of Byte): string;
// Decodes the Product Key(s) from the Registry

var
Reg: TRegistry;
binarySize: INTEGER;
HexBuf: array of BYTE;
temp: TStringList;
KeyName, KeyName2, SubKeyName, PN, PID, DN: string;

implementation

function IS_WinVerMin2K: Boolean;
var
OS: TOSVersionInfo;
begin
ZeroMemory(@OS, SizeOf(OS));
OS.dwOSVersionInfoSize := SizeOf(OS);
GetVersionEx(OS);
Result := (OS.dwMajorVersion >= 5) and
(OS.dwPlatformId = VER_PLATFORM_WIN32_NT);
PN     := ''; // Holds the Windows Product Name
PID    := ''; // Holds the Windows Product ID
end;

function View_Win_Key: string;
begin
Reg := TRegistry.Create;
try
Reg.RootKey := HKEY_LOCAL_MACHINE;
if Reg.OpenKeyReadOnly('\SOFTWARE\Microsoft\Windows NT\CurrentVersion') then
begin
if Reg.GetDataType('DigitalProductId') = rdBinary then
begin
PN         := (Reg.ReadString('ProductName'));
PID        := (Reg.ReadString('ProductID'));
binarySize := Reg.GetDataSize('DigitalProductId');
SetLength(HexBuf, binarySize);
if binarySize > 0 then
begin
Reg.ReadBinaryData('DigitalProductId', HexBuf[0], binarySize);
end;
end;
end;
finally
FreeAndNil(Reg);
end;

Result := '';
Result := DecodeProductKey(HexBuf);
end;

function IS_OXP_Installed: Boolean;
var
Reg: TRegistry;
begin
Reg := TRegistry.Create;
try
Reg.RootKey := HKEY_LOCAL_MACHINE;
Result      := Reg.KeyExists('SOFTWARE\MICROSOFT\Office\10.0\Registration');
finally
Reg.CloseKey;
Reg.Free;
end;
DN  := ''; // Holds the Office XP Product Display Name
PID := ''; // Holds the Office XP Product ID
end;

function View_OXP_Key: string;
begin
try
Reg         := TRegistry.Create;
Reg.RootKey := HKEY_LOCAL_MACHINE;
KeyName     := 'SOFTWARE\MICROSOFT\Office\10.0\Registration\';
Reg.OpenKeyReadOnly(KeyName);
temp := TStringList.Create;
Reg.GetKeyNames(temp); // Enumerate and hold the Office XP Product(s) Key Name(s)
Reg.CloseKey;
SubKeyName  := temp.Strings[0]; // Hold the first Office XP Product Key Name
Reg         := TRegistry.Create;
Reg.RootKey := HKEY_LOCAL_MACHINE;
KeyName2    := 'SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\';
Reg.OpenKeyReadOnly(KeyName2 + SubKeyName);
DN := (Reg.ReadString('DisplayName'));
Reg.CloseKey;
except
on E: EStringListError do
Exit
end;
try
if Reg.OpenKeyReadOnly(KeyName + SubKeyName) then
begin
if Reg.GetDataType('DigitalProductId') = rdBinary then
begin
PID        := (Reg.ReadString('ProductID'));
binarySize := Reg.GetDataSize('DigitalProductId');
SetLength(HexBuf, binarySize);
if binarySize > 0 then
begin
Reg.ReadBinaryData('DigitalProductId', HexBuf[0], binarySize);
end;
end;
end;
finally
FreeAndNil(Reg);
end;

Result := '';
Result := DecodeProductKey(HexBuf);
end;

function IS_O2K3_Installed: Boolean;
var
Reg: TRegistry;
begin
Reg := TRegistry.Create;
try
Reg.RootKey := HKEY_LOCAL_MACHINE;
Result      := Reg.KeyExists('SOFTWARE\MICROSOFT\Office\11.0\Registration');
finally
Reg.CloseKey;
Reg.Free;
end;
DN  := ''; // Holds the Office 2003 Product Display Name
PID := ''; // Holds the Office 2003 Product ID
end;

function View_O2K3_Key: string;
begin
try
Reg         := TRegistry.Create;
Reg.RootKey := HKEY_LOCAL_MACHINE;
KeyName     := 'SOFTWARE\MICROSOFT\Office\11.0\Registration\';
Reg.OpenKeyReadOnly(KeyName);
temp := TStringList.Create;
Reg.GetKeyNames(temp);
// Enumerate and hold the Office 2003 Product(s) Key Name(s)
Reg.CloseKey;
SubKeyName  := temp.Strings[0]; // Hold the first Office 2003 Product Key Name
Reg         := TRegistry.Create;
Reg.RootKey := HKEY_LOCAL_MACHINE;
KeyName2    := 'SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\';
Reg.OpenKeyReadOnly(KeyName2 + SubKeyName);
DN := (Reg.ReadString('DisplayName'));
Reg.CloseKey;
except
on E: EStringListError do
Exit
end;
try
if Reg.OpenKeyReadOnly(KeyName + SubKeyName) then
begin
if Reg.GetDataType('DigitalProductId') = rdBinary then
begin
PID        := (Reg.ReadString('ProductID'));
binarySize := Reg.GetDataSize('DigitalProductId');
SetLength(HexBuf, binarySize);
if binarySize > 0 then
begin
Reg.ReadBinaryData('DigitalProductId', HexBuf[0], binarySize);
end;
end;
end;
finally
FreeAndNil(Reg);
end;

Result := '';
Result := DecodeProductKey(HexBuf);
end;

function DecodeProductKey(const HexSrc: array of Byte): string;
const
StartOffset: Integer = $34; { //Offset 34 = Array[52] }
EndOffset: Integer   = $34 + 15; { //Offset 34 + 15(Bytes) = Array[64] }
Digits: array[0..23] of CHAR = ('B', 'C', 'D', 'F', 'G', 'H', 'J',
'K', 'M', 'P', 'Q', 'R', 'T', 'V', 'W', 'X', 'Y', '2', '3', '4', '6', '7', '8', '9');
dLen: Integer = 29; { //Length of Decoded Product Key }
sLen: Integer = 15;
{ //Length of Encoded Product Key in Bytes (An total of 30 in chars) }
var
HexDigitalPID: array of CARDINAL;
Des: array of CHAR;
I, N: INTEGER;
HN, Value: CARDINAL;
begin
SetLength(HexDigitalPID, dLen);
for I := StartOffset to EndOffset do
begin
HexDigitalPID[I - StartOffSet] := HexSrc[I];
end;

SetLength(Des, dLen + 1);

for I := dLen - 1 downto 0 do
begin
if (((I + 1) mod 6) = 0) then
begin
Des[I] := '-';
end
else
begin
HN := 0;
for N := sLen - 1 downto 0 do
begin
Value := (HN shl  or HexDigitalPID[N];
HexDigitalPID[N] := Value div 24;
HN    := Value mod 24;
end;
Des[I] := Digits[HN];
end;
end;
Des[dLen] := Chr(0);

for I := 0 to Length(Des) do
begin
Result := Result + Des[I];
end;
end;

end.

Bem, espero que seja útil como foi pra mim!!

DEBLUGADO