Power Switch not always working

Hey there, I just writing because I'm finding that the Power Switch to my Game Boy Advance is being very touchy and not always working. Sometimes I can just flick the switch and on it goes, but most of the time, I find myself having to be very careful in turning it on that I don't move the switch all the way or it'll just flicker on then off. I tried switching out the battery thinking that might be the problem, but that didn't work.

I'm worried something may have fried in there as my family moved it and some of my other consoles into the top part of the shed while I was out of town for the summer and the upper part of the shed is VERY above room temperature. I'm glad it even works, but I would also like it to work well.