You're getting some good tips on this and I found the link to Mic technique good.
Whatever mic you are using you will get this problem if its sitting directly above the computer. I've moved my Rode mic over to another purch to the side of the desk, and though its not very convenient it cuts down the hum and vibration quite a bit. I speak pretty close to the mic without encouraging pops. Sometimes I use a bit of base roll-off in the audio editor. One more thing which can help is a mic shock mount, which should isolate the mic from stand-borne noise. Hope some of that helps. Ray.
