Need help with single tailed LED

[test0r]

I'm a total modding amateur and hardly an electrician. But I have two spots on my case where I want a 5mm white LED to poke out from inside; I've got the holes drilled and finished, and the LEDs bought (from FrozenCPU - Tailed LED). I need to figure out how to run these without having to go out and buy resistors or do anything that is beyond my level. I also picked up some Molex-LED power cables (Power Cable) but when I spliced them together I got nothing. Can anyone help me find a solution that is not too difficult to implement? I'm holding up finishing my build for this because one of the lights will actually live under the motherboard and I don't want to have to take the mobo out later to re-fit.