White noise/hissing constant when recording?

ok whenever i record my vocals for a track there is this CONSTANT hissing whitenoise in the background throughout the whole track that is very noticeable and ruins the vocals. Nady smps-usb phantom power that i plug my NEW xlr cables in and from there the USB into my computer my microphone is a 1 large-diaphragm cardioid studio condenser mic (GXL2200); All new equipment. i have a gateway computer with windows XP and i record on cool edit pro 2.1 i know you can use audacity to get rid of the hissing but it distorts the vocals. I really need help finding a way to prevent the noise from even happening.