Sleep mode issues are very common.
First off, make sure all of your programs are closed. This issue is a biggie with win 8 and 8.1, because the tiles keep the last 4 apps open.
To check what is open in the tiles do the following
To close a tile or app while you are in it, (so you dont leave it open) save your work then press
ALT+F4 (some keyboard require you to use the FN+ALT+F4 or FN+F4)
The above will close the current app your on.
ALso you can view a list of the open apps by pressing keys
This will make a list of them on the left side go to think link to see this guide and a bunch of others for WIndows 8 and 8.1
If this is not the issue, and it usually is, because if the programs are open Windows will not sleep until they are all closed.
If not then try these steps from Vonnie Hudson's guides on windows.
1. Check your Power Options
Let’s try the obvious stuff first. It stands to reason that clicking Sleep should put the computer to sleep; however, those settings can change — let’s make sure they haven’t. Go to the Start Screen and type
Press enter and your power plan should immediately show up. Go ahead and click the blue Change plan settings link immediately to the right of your power plan
The Edit Plan Settings box will pop onto the screen. Click Change advanced power settings
The Power Options box shows up with a myriad of settings.
Scroll down until you see Power buttons and lid and then click the + (plus) sign next to Sleep button action to verify the action is really set to Sleep.
Pressing the sleep button is tantamount to popping an Ambien; however, the computer should sleep automatically when there’s no or minimal disk activity. I bet your settings are properly configured here – which is one of the reasons why this conundrum is so freggin’ annoying.
2. Generate a powercfg Report
Fortunately, Windows comes with a niffty little tool to make our sleuthing a little easier.
Press the Windows Key + x then press the letter “a” to open a Command Prompt with Administrator rights. You have to be an admin to pull of this trick.
Now enter this into the black void known as the Command Prompt:
After about a minute, you can view the Power Configuration report by browsing to the file location displayed in the results:
My report is a recondite webpage named energy-report.html sitting in C:\WINDOWS\system32\
Admittedly, the report reads as if it were designed for robots but not people, so it can feel abstruse and you might find yourself scrambling for an interpreter.
The other option is to run:
This will show you all the applications and drivers that are making power requests.
I don’t have any power requests right now, but when there’s a problem you might see the name of a device driver or an IP address that can help you narrow down the root cause. If something is requesting access to your computer, such as a SmartTV or media server, it can keep your machine up all night processing the request and you might see vestiges of it hanging out here.
3. Disable IPv6 or Leave your Homegroup
IPv6 is the latest edition and future replacement of the current IP addressing protocol known as IPv4. Most adapters have both versions enabled for backwards compatibility but you can safely disable IPv6 for now until it becomes ubiquitous.
Note: this trick isn’t really a solution but just a band-aid. Think of it like a transitory workaround until Microsoft fixes what I believe to be a bug.
Turning off IPv6
If you notice that disconnecting the Ethernet cable from your computer lets it peacefully fall asleep then disabling IPv6 in your TCP/IP properties might allay the problem. If this does the trick, it might be because you’re still running Windows 8.1 Public Preview or a buggy release of the RTM edition.
Visit the Start Screen and enter:
view network connections
Right click your Ethernet adapter and click Properties
Now scroll down to Internet Protocol Version 6 (TCP/IPv6), uncheck it and click OK.
Leaving the Homegroup
Homegroups are a great way to share media resources with family and friends at your home. It lets you share all your music, videos and printers with just a few clicks; however, for some reason Homegroups are infamous for stopping the computer from catching its zzzzzz’s.
The simply workaround is to leave the Homegroup.
From the Start Screen enter
then click Leave the homegroup and choose Finish.
4. Close all applications
The last thing to check is to make sure every program you can feasibly close is actually closed.
For example, if you leave VLC Player open, or an Internet Explorer window active in the foreground the computer probably won’t fall asleep by itself.
Also, make sure Skydrive is off because Skydrive does a lot of background synchronization which can keep the machine actively sending data to and from the Cloud. You can close SkyDrive by typing
Next, from the Start Screen clicking the toggle switch to Off.