HP Compaq Presario,Presario 1515 Supplementary Manual page 27

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Observe your typing style and notice how you use your fingers and hands. Avoid
keeping any unnecessary tension in your thumbs and fingers. Observe whether you
have a heavy touch or a light touch while typing. Use the minimum amount of force
needed to depress the keys.
To reach keys that are not near your keyboard's home row, move your whole arm;
avoid stretching your fingers and angling your wrists. When pressing two keys
simultaneously, such as
to reach both keys
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or use two hands instead of contorting one hand
Relax your thumbs and fingers while typing and pointing;
notice and release excess tension.
Don't type or point with unnecessary tension in your
thumbs and fingers.