I've had this problem for a year now, sometimes when i turn the lights on, my computer (running Windows 8.1) automatically turn on from sleep and I have to put it back to sleep again, but this almost happens every time i turn the speaks on and off or anything else connected to the same power outlet as the PC power supply. I'm using something like this for my PC, monitor, speakers etc.
My PC has a 850W PSU that is 4-5 years old. I've always kept it clean and used air filters for dust. its fan works fine and the PSU is locate at the bottom of my case so it doesn't take too much heat. I changed the power plugs, my room and even house (not for the sake of this problem of course!) but the problem is still there. It might be a little electrical but I need to know where the problem is and solve it without changing my current PSU. Thanks
UPDATE: I found a question in here and it's different than my situation. I'm not using USB hub and it even happens with something like turning on a light which doesn't need so much power. I also changed my house recently and still having the same problem, so there shouldn't be a circuit problem in every house. BTW i'm using a wireless laser mouse and 2 AC fans connected to the same power outlet and sometimes back of my case or sides have some weak electrical current.