I had this problem, and this is the only way I could cure it.
(Windows does have sleep button options.)
1. Click on the Start Button
2. Open the Control Panel
3. Click on Power Options.
4. Click the Advanced tab.
5. Locate the "When I press the power button on my computer" drop-down menu.
6. Select "Do Nothing"
7. Locate the "When I press the sleep button on my computer" drop-down menu.
8. Select "Do Nothing"
9. Click OK
Now the cat will have to select shutdown the normal way by clicking the start button and selecting "Turn Off Computer". (So will you)