I recently built a computer that has one eVGA Geforce 7800 GTX video card. What im confused about is water cooling set ups. The fan and heatsink are screwed on the card with these square type screws. I'm new to water cooling and im wondering, when i buy a GPU block, do i remove the fan somehow? Do i even remove it? Are certain water cooling set ups not compatible with this card? can someone explain in depth about this.