you can get the squeal out of the rotor by cleaning and sanding. you can't get the squeel out of pads by sanding, or lighting them on fire, fun but doesn't work. replace the pads. also test ride the bike to test the braking performance. can you skid the rear tire? can you lift the rear end when you apply the front brake? if the power is low i would question the condition of the pads if the lever feels ok.