建立：
var
  aReg: TRegistry;
begin
  aReg := TRegistry.Create;
  try
    aReg.RootKey := HKEY_LOCAL_MACHINE;
    aReg.OpenKey('SOFTWARE\Microsoft\Windows\CurrentVersion\Test',True);
  finally
    aReg.CloseKey;
    aReg.Free;
  end;
end;

刪除：
var
  aReg: TRegistry;
begin
  aReg := TRegistry.Create;
  try
    aReg.RootKey := HKEY_LOCAL_MACHINE;
    if aReg.DeleteKey('SOFTWARE\Microsoft\Windows\CurrentVersion\Test') then
      ShowMessage('刪除成功')
    else
      ShowMessage('刪除失敗，可能原因不存在!');
  finally
    aReg.CloseKey;
    aReg.Free;
  end;
end;