fans inside are very noisy there running on high speed

have a HP Pavilion a708.uk PC. I have added Graphics card, extra memory and added a 2nd internal HD. All been working good and fans have been silent only working on initial start-up and starting up when get hot.

But a few weeks ago my HP motherboard went at first because things were not working I changed the PSU for a `Trust` 370 watt model this is a Low Noise
Model. Then I realised the actual motherboard had gone. I changed the
Motherboard for an `ASRock P4VM900-SATA2` model now it’s all working
But the fans inside are very noisy there running on high speed

On the HP Motherboard the fans were controlled but on this new one there not.

What fans shall I get that can be temperature controlled and will run silent. I think I will need 2, the main one for inside and the one over the CPU