If you open up your power switch/socket by unscrewing the 2 screws, you will see something like a box inside the wall with 2 protruding legs/compartment which is used to hold the 2 screws.

One of the leg/compartment in one of my power switch is now broken. How do i fix this?

I dont think i can change the whole box itself since it's embedded inside the wall. If i use super glue to fix the broken leg/compartment, i dont think it will last/within the screw for long term.

Any one has an idea on how to fix this?

you can try drilling the broken hole, and stuff a wall plug in. if you want I suppose you can hold the wall plug in with super glue as well though that's probably unnecessary.

the whole box inside the wall itself is made of plastic and the whole leg broke off. so the only way to drill is to drill through the box into the wall. quite a big hassle here. and also not familiar with the wiring.

you just need to drill the part where the screw needs to be. I've seen it done before. no rewiring necessary.

Drill pass the plastic box, add a Get longer screw, and you need a filler (don't know the term here). After drill the hole fill the hole will rubber / wood filler, then your long screw will be able to screw in easily with the face place.

BTW, i don't use filler, i use bamboo chopstick as filler.

your method works. thanks.