Monitor flashes when I turn off electrical stuff

[-TesseracT-]

Guise, Im still worried. I posted this topic 

 about how when i stood up from my chair, my monitor would flash for like, 1 sec. Now, when ive moved, that doesnt happen as often (when i stand up). However, it happens when I turn off my ceiling lights or my table fan. Not only does the screen go black, but the audio (when im using the monitors speakers) goes out for like 2 sec.

 

Im just want to know why this is happening, what I can do, i dont want my monitor to break (it was expensive). My room is not humid, the wall sockets are grounded, my chair is not on carpet, my house was built in 2005.

[karsnoordhuis]

just a bit of a guess but it could be poorly shielded cables. as you said, it happens when you turn off a fan or ceiling lights.

this creates a change in magnetic fields.

this is the only thing i can think of.

[Frankenburger]

This used to happen with my 40' TV. Pretty sure it was an issue with power delivery. Once I put the TV on a UPS, the issue went away.