noisy discs

Impossible to dtermine with out looking.

Are the rotors clean and straight?

Are the rotors hitting the pads?

The sources of squeal are:

-dirty pads or rotor
-misaligned caliper
-misaligned mounting hardware (frame or fork tabs)
-damged components

Most likely it's the pad to rotor alignment, which should be parallel and perpendicular and centered, if 2- or 4- piston system.

The next most likely problem is contamination, so use Isopropyl Alcohol to clean the rotor and pads....

Any more details you can give?