All I know is to tiptoe.....
Yep ... Hire a contractor, unless you know construction.
It requires finding the floor joists, and "reattaching" the subflooring to the joists.
I heard that sprinkling baby powder then walking over the squeaky area a few times, then sweep up the excess works on hardwood floors.
Are we talking hardwood or carpeted floors? If it carpeted floor they have special screw to fix it. Watch this video.On hard woods, I know people who have used baby powder.