windows 8.1 won't go into sleep mode,

I've been experiencing this also since updating to Windows 8.1.  If I manually put the PC to sleep it comes right back on again.

I tried changing the homegroup a few times, doesn't seem to help, maybe 8.1 is different. I know it is frustrating.

It does seem to be the adapter, but I do not have any other computers that I am sharing files with. I did close the adapter yesterday, and it went into sleep mode most of the day. But this morning it went back to the same old thing. It must be one little thing. I have tried stop sharing in some things, but moving around in 8.1 can be confusing at times. I would assume someone on the boars would know more about it.

Check out this link....

http://forums.anandtech.com/showthread.php?t=2329266

I have not had a chance to try it myself but I'm hopeful this guy has the solution!  Here's the text from his post at the above link.

"K, I solved it! It is an issue with HOMEGROUP in Win8.1 Pro. Mind you, the HOMEGROUP computers that are preventing sleep don't even have to be turned on! Basically, I had to take the three computers in the house, unshare ALL files/folders (shift-left click to select all files and folders, right click-sharing-stop sharing), and have them leave the old HOMEGROUP. I then created a new HOMEGROUP with a new password and made sure that I could share files and folders back and forth. 

To verify that this is your problem, just disable the network adapter and set the sleep to one minute. Wait 5 minutes and see if it sleeps. EDIT: You may need to unshare all files/folders on the computer before this will work.

Now the two Win8.1 Pro computers sleep! (takes a couple of minutes to fall asleep so some patience is needed).

I now have two others that have had this problem and my fix worked for both of them. I wish I could submit a MS bug report..."

I am beginning to think I should not of installed 8.1 Having some video problems with flash player also. Don't see a way too do it.