Magnets and Computers

HI I was wondering if anyone can answer me this question. "Do magnets ruin computers? The Hard drive? "
If so then can anyone answer me this question why is there such a strong magnet inside the hard drive. I say strong because I took and old non-working hard drive and found a magnet on the inside and I took it out and stuck it to a metal filing cabinet and took a heck of a time getting it off. But this brought up the question because I was always told that putting magnets inside the computer could mess it up.

 

Yes, they can, but read on about the purpose of it.

The Head Actuator

All the heads are attached to a single head actuator, or actuator arm, that moves the heads around the platters. Older hard drives used a stepper motor actuator, which moved the heads based on a motor reacting to stepper pulses. Each pulse moved the actuator over the platters in predefined steps. Stepper motor actuators are not used in modern drives because they are prone to alignment problems and are highly sensitive to heat. Modern hard drives use a voice coil actuator, which controls the movement of a coil toward or away from a permanent magnet based on the amount of current flowing through it. This guidance system is called a servo.

 

OIC , thank you for that explanation. answers my question.