Ok this is a weird one that I have no idea how to solve. At first, my computer was randomly turning itself on, so I fixed that by changing some setting in my BIOS.
Here is where it gets weird. The computer is still turning itself on by itself when it is in sleep mode. Here is how it has happened two times now. While my computer is asleep, when I flip the light switch on the wall to turn off my ceiling fan, the computer wakes up. This only happens when the computer is sleeping, not completely shut down.
How can I fix this and should I be worried (could this be damaging the computer)?
Just wanted to give you an update on this situation. I switched wall outlets (same room/same circuit) and it fixed the problem for awhile, but now it has returned. I have a UPS now, and it says the input voltage is fluctuating between 123-124. The voltage doesn't do anything abnormal when turning the fan off, just remains at 123-124, which leads me to believe the spike is happening so fast the UPS can't pick up on it.
However, I am more inclined to think my computer is just possessed because today it turned simply by me touching the case.
It's clear you have a floating ground somewhere in your house wiring. I would call a licensed electrician to have him check the panel and wall outlets throughout the house.
On second thought... Does your computer act the same if it's at another location entirely? Like at a family members house? I'm starting to suspect it may be a bad ground in the computer - did you build it yourself?