CM EXTREME 550 VERY LOUD

HI All,

I have a question about my power supply, it seems to be the loudest part of my system and its bugging me.

I have a cm 690 case with a extreme power 550w ps.

I do not have much hooked up to it, imo, for it to have the fan on full blast all the time.

it says that there are two 12v rails at 16a each

my system is

asus p5k-se
e2160
8600gt silent
2 gig ddr2 667
lg dvdrw
80 gb hd wd
200 gb hd wd
4 case fans 12cm.

Im am trying to have a fairly quiet pc. Im using a zalman 7700 cpu cooler on lowest setting and i dont hear it, ive put all fans to a vantec fan controller and all on lowest setting,

ive tried stopping the fan and i know its the source of the noise,

I have also tried venting it inside and ourside as my case allows this.

Any suggestions as to why the fan would be on all the time? I looked to see if there was a lead to connect to the mb for the fan to be controlled but there is none...the room is only about 22c so there should not be any heat issues.

thanks in advance for your help.
kev

I do want to buy a better psu, but i find many of them are over 100$.

im going to have to calculate how much i do need what then decide how much power to get.

thanks for the help