One way to make case fans very quiet is to use good quality PWM fans attached to the CPU fan socket through a powered PWM splitter, for example http://www.overclockers.co.uk/showproduct.php?prodid=CB-031-AK.
Enermax T.B. Silence fans are pretty quiet I seem to remember, don't shift much air though.
Depends on the motherboard, but in most cases you would need to adjust the speed manually, either in the BIOS, or with a program such as SpeedFan.so you cant control fan speeds from motherboard when connected to SYSFAN1 or 2 etc?
so i need one of those splitters with the CPU and TWO fans attached and they will speed up with the CPU fan? - and I need PWM fans? or does any fan work with them?

Arctic F12 PWM, see http://www.arctic.ac/en/p/cooling/case-fans/73/arctic-f-pwm.html.ive told him the fans are about £10 each and £4 for CPUFAN adapter.. hopefully he will choose this one, can anyone recommend two 120mm quiet PWM fans for about £10 each~?