Windows Vista has the System Beep enabled by default. Every time you encounter an error or security warning you will hear a beep. If it becomes very annoying to you there is a way to disable it.

Steps to disable system beep:

1. Go to Start menu and right click on Computer. From the context menu choose Manage.

2. In the Computer Management window go to System Tools and choose Device Manager.

 3. Go to the View menu and select Show hidden devices.

4. If you return to the Device Manager you will see a category of devices called Non-Plug and Play Drivers. Expand that list and select the Beep, as shown in the figure below.

 5. Right click on the Beep and select Properties.

6. In the Beep Properties window go to the Driver tab. From the Startup scroll down list, select Disabled and press OK.

 7. Restart your PC.