1997 Nissan 240SX Weird squealing sound

Noises problem
1997 Nissan 240SX 4 cyl Automatic 100000 miles

When I start my car and begin to accelerate, around 2rpm, I begin to hear an increased sound from my engine, but when I reach 3rpm, a loud squealing sound begins and does not let up until I release my foot from the pedal, or the car shifts and reduces the rpm level. After spraying the belts with belt dressing, it has not changed. A year ago, we found out it was a problem with the mass air flow system, which we got fixed, and has not been damaged or show signs of need to repair. Any help would be greatly appreciated. I've been told it could be from worn out fan belt, or one or more of the pullys.