Case fans not working

I know there have been alot of other people with a similar problem, but when i tried using search function i just got a "thread does not excist" message, so i guess ill ask again :S

I resently baught 2 Arctic Cooling 80mm fans for my case, since i found out that my gfx card was running at 70C when idling. However, for some reason, they arn't active when i turn on the computer.
I placed them on the back pannel since that was the only obvious place i could put them. On the fans there were 4 pin sockets and 3 pin plugs, i put a 3 pin plug from each fan into seperate 3 pin sockets on the motherboard (im using a Gigabyte GA-EP45-DS3P motherboard), which were labeled sys_fan1/sys_fan3 in the users manual for the motherboard. Each socket supplies 12V, which according to the instructions on the fan boxes are what they require, and according to the manual the sockets are used for case fans.

I have tried looking through the BIOS sections, but since im not really a wiz at this stuff im a bit apprehensive about touching any of the settings there, and i couldnt find anything related to fans, except a section under PC Health Status that indicated that my fans were running at 0 rpm .

Anybody have some ideas as to what i could try?

I couldnt find any 4 pin sockets that were connected to my power supply, so i opted for connecting my CPU fan to one of the fans and then connecting that fan to the other fan and then to the CPU socket on the motherboard. According to the fan instructions it should be OK, but i would've liked to be able to attach the fans to their individual sockets.

Thanks for the reply though