SilentStriker has probably said all thats needs to be said.... BUT, depending on your microphone even with Noise Removal, you may still get a tiny amount of background noise.
Another useful thing is to have the 1.3 Beta of Audacity which is also free if you don't already use it. The only difference really is that when removing noise, you have more options of what you want to be removing. I prefer it like that as I found with the older version of Audacity that sometimes it wouldn't do a great job e.g. robotic sounds and still has background noise.
You may also want to altar some of your microphones settings to get the best sound quality for recording too if you can. Like removing special effects for music and so on.
Hope this helped