I am new to system building so this will probably be a very basic question to many of you. One of the many questions I have about this process is CPU cooling. Is there a differenc between a heatsink and a fan. Do I need to use a theraml plate or thermal paste? What exactly is thermal paste. I will be building two machines in the nest few weeks both with 750 Durons with the possibility of slight overclocking. What so I need for CPU cooling? Thank you very much for your time.