Open Cool Edit Pro from your computer's desktop screen.
Click "File" at the top of the Cool Edit Pro window and click the "Open" sub-option.
Locate and select the MP3 file you desire to cut. Then click "Open" to load the song as a waveform in Cool Edit Pro.
Press the "Play" button to start the MP3 playback and determine where you'd like the cut to begin. Press "Pause" where you want to begin the cut of the song.
Drag the mouse to the right over the MP3 waveform to highlight a portion of the song.
Right-click over the highlighted region of the MP3 waveform and click "Trim" to cut out the excess of the song. Press "Play" again to review the song.
Pause the song toward the end of the cut where you'd like to stop the MP3. Drag the mouse to the right side of the waveform again to cut out the remaining excess of the MP3.
Click "File" again, and select the "Save Selection As" option. Type a new name for the cut of the MP3 in the data field on the pop-up box. Then click "Save" to store the MP3 cut to your computer.