Why doesn't my VAIO notebook display "VAIO logo" nor produce a booting sound when I turn it on?

My machine used to display "VAIO logo" upon turning it on and right after system recovery but it doesn't do that any more.
Even if I execute [Get Default Values] (initialization of the setting values of BIOS) on the setting window of BIOS, the situation does not change. Why is that so?
* "VAIO logo" is the function that animates the logo of "VAIO" and produces sound after the "SONY" logo appears when the computer is turned on.

"VAIO logo" is disabled if the following is carried out:
- When [Get Default Values] (initialization of the setting values of BIOS) is executed on the setting window of BIOS.
- When the [Default] button on the [Sony Notebook Setup] dialog box is clicked.

To enable "VAIO logo" again, please refer to the procedure below:

--Procedure--
1. Click [Start] -> [VAIO] -> [Notebook Utilities] -> [Sony Notebook Setup].

2. Click the [Initial Setting] tab and check the [Show VAIO logo] box.

3. Click [OK].