Alright, so i have a new computer

and i want to start casting some stuff, my computer is pretty good (no lag running borderlands on maximum, no over clocking) but here is the thing,

I have no idea wtf I am doing when it comes to casting and I know live-stream is nothing but dicks when it comes to casting, so what I'm asking is what would be the best way of casting?

I'll try and gather my specs so you people will know with what i have to deal with hardware wise.

EDIT: Specs i know of

Video Card: AMD Radeon HD 6800 Series

CPU: AMD Phenom(tm) II X4 955 Processor

OS: Microsoft Windows 7 Ultimate Edition Service Pack 1 (build 7601), 64-bit