However, it just put my PC in sleep mode. After that I’ve never used this button again until today. By exploring Advanced settings in Power Options, I realized that I can configure this power button.
Click on Power Options and Select a power plan window should be displayed on your screen.
This is a window where you can select your power plan. Under each plan you can see Change plan settings link. You should click on this link in order to navigate to Edit Plan Settings window.
We are not there yet. Click on Change advanced power settings link, and you’ll see Power Options window.
Almost there. In the list section of that window extend Power buttons and lid and then extend Start menu power button. In Setting change from default Sleep option to Shut down one.
Press the OK button and you are finally done. Now the power button is going to shut down Vista.
Also notice that before the power button was brown and now it’s reddish.