Power Button not saving selected option

so I turned on the computer today and the start menu power button was mysteriously back to the sleep option. I went into the power options and it was set at "shut down" for the button. I reselected it and hit save and nothing. It wont change from sleep mode. Two questions, why on earth would this change itself and why on earth wouldn't resetting it change it back?

Vista 64 bit Home Premium

Hello Squa,

Double check to make sure that you have the correct power plan selected that you are making the changes to. It's real easy to bump the scroll button on the mouse and change the power plan.

http://www.vistax64.com/tutorials/68146-power-button.html

Hope this helps,
Shawn