Since getting your computer to sleep is new to you, I will give a brief summary to get you started. Search the web for details.
The first thing you should know is that you cannot always get your computer to sleep reliably. It may not wake at all, or some things may not work properly after the computer has been sleeping one or more times. Reliable sleeping needs the hardware and hardware drivers to work correctly. However, modern systems are much better, and there is a good chance they will work properly.
The Control Panel is used to configure how the computer sleeps. Go to: Control Panel > Hardware and Sound
Then under “Power options”, click on “Change when the computer sleeps”
There are several power states:
Off: Zero power used. The computer is unplugged, the battery is removed, or the switch at the back of the computer is flipped.
Soft Off: Usually 1-5 watts used. The computer is shut down. Most of the hardware is powered down, but the power switch works. A USB remote receiver cannot wake the computer from this state; you need a remote receiver that is connected to the motherboard’s big power cable. A few motherboards have special headers that can also be used. An example of a remote receiver that is connected to the power cable is:
(Note: I have not tested this remote receiver. My HTPC case has this functionality built in.)
Hibernate: Usually 1-5 watts. This state is the same as Soft Off, except that when it hibernates, the computer’s entire running state is written to disk before it shuts down. When the computer is wakes, it reads this data and restores it to the state (running programs and all) that it had before hibernating. Waking from hibernation requires the same special hardware as Soft Off.
Sleep (S3): A bit more power than Soft Off or Hibernation. In Sleep, more of the system is powered. (A power outage while sleeping will crash the system.) The RAM stays on, so the computer can wake in just a few seconds. USB remote receivers, keyboards, and mice can wake the computer, if the power setting in their drivers is set correctly. Wake on Lan (WOL) can also wake the computer. To do this you will need to set the network driver to wake on a magic packet. You may also need to change a BIOS setting.
Hybrid Sleep: The same power as Sleep (S3). This is the same as Sleep (S3) except that it also saves the running state to disk, just like in hibernate. A power outage while sleeping will not crash the system, instead it will wake like it wakes from hibernation.
P.S. There are devices that can turn other equipment on or off depending on the computer’s power usage; they can power the equipment off when the computer is sleeping, and power it on when the computer is awake. I do not know if this could be used with an XBOX.