Under "Power Options" you are able to change what certain things do in regards to sleep, hibernation, power consuption, shutdown, etc. One of the settings is to control what certain buttons do when you press them. These options can be found on the left side of your Power Options Window.
Access Power Options:
1) In the start search bar type Power Options and hit enter.
2) On the left you should see some options "Choose what the (name) button does".
3) If you're using a laptop you should have some options such as "Shutdown Button", "Sleep Button", "On lid close", etc.
4) Most likley your Sleep Button setting is set to "Do Nothing". Make the desired changes and exit.
Running Windows Vista Home Premium on a HP computer, model A6130N.
Whenever I go to push the Sleep button on the keyboard, the monitor will turn off and nothing else will happen. I go to move the mouse, the monitor turns on to the login screen. Before last night, it would go into sleep mode with no problem, even after I set my wireless adapter and on-board Ethernet to allow my Xbox 360 to connect to the internet, it went into sleep mode. I've tired restarting it and changing my wireless/ethernet to their previous settings, but it still doesn't go to sleep mode. I even installed the driver Vista recommends for my on-board video card. Nothing.
Any help would be appreciated.