I am a newbie and recording voice and keyboard…I checked help and couldn’t quite figure out how to sole problem. Audacity said to go to go to preferences and I believe effects and I was lost at that point. Also don’t quite understand how to mark the area in the beginning before the music and vocal begin?
About selection, have you read the last reply you received: How do you trim each end of the recording of a song ?
You run effects from the Effect menu, not from Preferences. However you can’t remove random noises like a whisper or a bang with the Noise Reduction effect - that is only for steady noise like a hiss. Random noises may need dealing with individually according to what they are.
How are you recording voice and keyboard? Both at the same time with a microphone? Can you attach an audio sample of the noises you want to remove? Please see How to post an audio sample.
Generally I suggest you do yourself a favour and make sure you have the current Audacity 2.1.3 release from Audacity ® | Download for Windows.
Then our documentation http://manual.audacityteam.org/ will match with the version of Audacity you are using.