angeldevimon :
my recommendation -
PC : cubase.
Mac : protools.
protools on PC = Protools M powered (your audio interface will need to be somethin m audio)
yes you will be able to do anything as long as you read the manual and be familiar with your DAW.
Processor intel's fine. mobo Asus is usually my option. cooling - well does your room have aircon? if you get 2 hdds avoid stacking them right next to each other.heat.
ram ok, hdd ok (I think. sorry I got 7tb. i don't know how to gauge).
noise wise, the more hdds/fans you have running the noisier. so try to isolate during recording or go bios to temporarily change the performance of the fans to "silent" for slower rotations or somethin. or somehow isolate your PC in a well ventilated + cupboard, or in another room even better.
OS : win7 i can't recommend well cos i'm still on winXPsp3, but at 6gb ram i'm assuming you're going 64 bit ? cos 32bit OS only can recognise up to 4gb max.
graphic card : even an onboard VGA will do.
PCI audio interface slots are soundcards that look like these :
http://www.echoaudio.com/Products/PCI/MiaMIDI/index.php
whereby you directly plug it into the motherboard.
audio interface are actually just "Recording Soundcards". the difference between these soundcards and your onboard creative/realtek audio soundcard is that one's made for recording, one's made for "playback" consumer use.
if you read
http://tinyurl.com/diyrecording, there's PCI/USB/Firewire audio interfaces. each has its pros and cons. calm down, there's alot to learn, the best thing is it gets addictive from here.the more you learn, the more things there will be for you to learn/discover.
cheers