First, to install the cooler, you'll need some instructions that should come with it.
Second, the card should work on your machine with a better PSU of course. But are you aware of the X1600 "frezzing problem"? X1600 cards, especially sapphire's (and AGP cards) freeze whenever 3d is rendered. Just check the reviews on Newegg.com and you'll know what I mean.
Third, " a thinking sound"?? What do you mean?