Getting rid of background noises on mic?

My microphone keeps picking up background noises, like me breathing, my mouse and keyboard clicks. I've tried lowering ALL of the microphone "Levels" in recording settings to 0 and plugged my mic into different USB ports and I'm still getting noises, which doesnt make any sense to me.

I'm using Windows Home Premium, the Logitech New Clearchat Comfort headset/mic and the soundcard is listed as USB Audio Device (associated with the headset I'm assuming..)

I had one of those some time back and had nothing but problems with them, so I returned them. I don't think it's anything with the settings but with the headset themselves. Looking on Logitech's website, they're not even listed anymore. I would recommend a gaming quality headset, well worth the investment IMO.

I use Razer.