What kind of things are you recording? One person talking in a quiet office? A group talking in a conference room? Interviews on a busy city street? People singing? What kind of noise? Your computer fan? Cars driving by?
The most effective way to reduce background noise is not to capture it. Use a directional (cardioid or super-cardioid) microphone aimed at and close to the person or people speaking or playing. If multiple people are speaking, best results are often a microphone for each person, and a mixer to combine them. Record in as quiet a space as you can. Turn off the stereo in the background. Close the office door. Maybe shut off the ventilation fan.
There isn't much you can do to remove background noise once it has been captured by a microphone. Just about any filters etc. will affect the sound of the voices as well.