be specific

Hey, its great that your getting in to music. thumbs up!!
but one question, what do you want to do. You want to build a PC
thats fine and simple, but if your not even sure, what you want we cant help you. What you want to make> what is your budget? All depends. Its like I want a car, do you want a ferrari, toyota? BenZ?

Well for a starter, If you are advanced I recommend you to build a AMD based computer, I recently got a 248 dual OPTERON, it is really fast, and helps when you have a lot of tracks,
but until I got this I was just using a 2.5pentium4,
again, budget is a key issue here.
Also there is Protols, Sonar, Cubase Nuendo, to choose from,
sound cards, digi 001, 002, RME fireface many many options.
Look in to what kind of music you want to do.
If you just want to start out, I reccomand you a 700dollar
computer with at least 200gb of space and 1gb or ram
and get a MBOX, with the factory bundle. it helps to start out.
then build yourself from there, if you want to record using midi,
just get a vsti, like sample tank hypersonic etc...
lots of options, try everything out and build your system,
if you have the basis, then you can always add on and that is the fun part of it. It is always good to ask at first but always trust your ears and your mind, if you can do that you are going to be successful in someways at least, so good luck if I can help in anyways let me know, Im always willing, ofcourse at no cost :P
so good luck!! and all the best

ALLFORONE.

For the computer, I would get a Pentium 4, no doubt.
Boy did I screw up getting an AMD and then using a Delta 1010. Got these "pops" and "clicks" on random tracks. Doing research on the issue I found that this was a "known problem" with AMD processors. They just lack the compatibility of Intel.
AMD is great for gaming power on a budget; but don't use them if you're doing serious processing like video or audio. Save yourself a headache or ten and get a Pentium.

I'd also cut out the need for quantity in hard drive space, in exchange for "quality". Pickup two SATA Western Digital 10,000 rpm Raptor drives and set em up in a RAID-0 config. Combined with a healthy amount of RAM, you'll have a speedy computer for audio editing.

For multi-track recording, you might want to get an 8-track analog/digital computer, like the Delta 1010. Echo makes them also. Sometimes those thigns come with software packages. If not, get something like Sonar or Adobe Audition. Then you need a preamp or mixer to get the signal in to the analog/digital converter; depending on your needs/wants there are thousands of ways to do this.

If you're only doing something simple - 2 tracks or less, then get the USB Mobile Pre-amp from M-Audio. Very easy, simple and great quality for the price!

Boy did I screw up getting an AMD and then using a Delta 1010

Well I got an AMD and it works great, its all in the application

I plan on getting a firewire based 8 channel i/o box soon, but for now what I have suits me fine