[Serega]

простой кусок кода по сути в качестве примера, по аналогии я его размножу. »

Пример

Код:

[Setup]
AppName=My Program
AppVerName=My Program 1.5
DefaultDirName={pf}\My Program
OutputDir=.
Compression=lzma/ultra
InternalCompressLevel=ultra
SolidCompression=yes

[Languages]
Name: russian; MessagesFile: compiler:Languages\Russian.isl

[Files]
Source: compiler:Examples\MyProg.exe; DestDir: {app}; AfterInstall: BackupReg; Flags: ignoreversion

[code]
procedure BackupReg;
var
  res: Integer;
  BackupDir, Key, RegEdit: string;
begin
  Key:= 'HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\Inno Setup 5_is1';
	BackupDir:= ExpandConstant('{app}');
  RegEdit:= ExpandConstant('{win}\regedit.exe');
	Exec(RegEdit, '-ea backup.reg ' + AddQuotes(Key), BackupDir, SW_HIDE, ewWaitUntilTerminated, Res);
end;

procedure CurUninstallStepChanged(CurUninstallStep: TUninstallStep);
var
  res: Integer;
  reg: string;
begin
  reg:= ExpandConstant('{app}\backup.reg');
  if CurUninstallStep = usUninstall then begin
    // при деинсталляции, заносим ключ в реестр
    if FileExists(reg) = True then
    Exec('regedit.exe',' /s ' + AddQuotes(reg),ExpandConstant('{win}'),SW_HIDE,ewWaitUntilTerminated,res);
  end;
end;