Help a noob with LED and resistor

[Kotaris]

I was earlier directed on how to calculate what resistor I'd need. But for some reason I just seem to be doing it wrong. I plan on using a Red Cree LED and not sure what to use with it.
Also, should I use a buckpuck or resistor? And what kind of difference does it make?

[darth_chasm]

Post your calculation. Can't really see where you think you may be going wrong.

i saw your other post and if you are still planning on using the NB then don't worry about a buck puck.

[DarthFender]

Also, if you want us to calculate it for you you have not given us enough information. I suspect that if you get all the information together, the calculation will make sense.