I don't have one either.. Apparently, it's the "Sleep" button on certain types of keyboards and causes the computer to go into Standby mode.. If it's not waking from "Sleep" correctly, then you can disable the Standby options or try updating your chipset drivers to attempt to fix the ability to Sleep correctly..
To disable the Standby option, you should be able to RIGHT click on the desktop, choose "Properties", then the "Screen Saver" tab, then the "Power" button, then the "Advanced" tab, then see: "when i press the standby button", choose "do nothing".
A little research shows that pressing the moon key again, or the Esc key, or possibly pressing the power button quickly should bring the computer out of Standby IF it's working correctly.
It also appears that you might be able to disable the moon key's ability by changing the Energy Saving settings in the same Screen Saver-Power section as above.
Hope this helps.