Computer Running By Itself

I'm not really sure which thread to post this in. I'm certainly no expert when it comes to computers, but I can't help think something is up. Normally, when I'm done using my computer, I will push the "sleep" button to turn it off. Up until approximately six weeks ago this had been an effective way of turning it off for the night. It would stay off until I turned it on again. Since around mid-late July, my computer has been turning itself on and running, usually for several hours at a time. It doesn't seem like it's actually doing much, if anything, while it's on. It will then shut itself off for five or ten minutes, maybe even a little longer and then turn back on again.

I have clicked the "Start" in the bottom left corner of the screen. Then I type "task" and click "schedule task". When I check tasks that have run in last hour, I can't find anything. It shows nothing. If I click on "Display all running tasks", it will list these;

- Cache Task...Wininet Cache Task...Microsoft\WindowsWininet
-MsCtf Monitor...task handler...Microsoft\Windows\Task Services Framework
-System Sounds Service...Microsoft Play Sound...Microsoft\Multimedia

My computer started doing this around the time that Windows 10 became available. I haven't started using Windows 10. I'm still using Windows 7, but my Internet Security program did download it's Windows 10 compatible version.

My question is, does the fact that my computer is running by itself have anything to do with Windows 10 or does it have a virus that my Internet Security program hasn't detected? Do the three tasks listed above need my computer to turn itself on? If not, how do I stop this from happening? I would like my computer to not run unless I turn it on, just like before.

Thanks in advance

Hi Leo6,
I am no expert or anything, but I could doubt the schedule task.
However, after ruling that out, do you think it is possible that your laser mouse (confirm if you have one) could be waking up your computer?
What are the active settings you have for waking up the computer.

Some BIOS would allow computer to be turned on by LAN, MOUSE, KEYBOARD. Can/DID you check your BIOS settings for waking up?