2001 Mitsubishi Montero LOUID SQUEEKING

Air Conditioning problem
2001 Mitsubishi Montero 6 cyl Four Wheel Drive 86,000 miles

I HAVE READ SOME OF YOUR PROBLEM SOLVING ANSWERS AND I THINK YOUR GREAT.
I CAN;T SEEM TO FIGURE OUT THIS PROBLEM I AM HAVEING WITH THE AIR CONDITONING IN MY 4WD
MONTERO SPORT(86, 00MILS) THE PROBLEM STARTED LAST SUMMER WHEN I TURN ON THE A/C AND I'M NOT IN MOTION, THE CAR IS STANDING THE A/C BLOWS COOL,
BUT WHEN I START TO DRIVE AND I HIT 25MPH OR MORE THE CAR STARTS TO MAKE A VERY LOUID SCREEMING NOISE AND THE AIR STARTS TO TURN WARM. I HAD ALL THE BELTS CHANGE AND MORE AIR REFRIDENT PUT IN AND THE NOISE STOP FOR
TWO WEEKS AND THEN IT RETURN.