Building a Music PC There are about a million ways you can go about building a computer built for music. Here’s a short list to get some ideas rolling in your head.
A typical windows machine (In My Opinion)
Operating system (OS): Windows XP (Service Pack 2) and above…
Note: Upgrades & patches for older software prior to the release of Vista is slowing rolling around… there have been some known compatibility issues in the past but most of them are resolved and should be fine by now…
Memory: At least 1GB of RAM 2-4GB is preferred (especially if you are planning on using Virtual Instruments (software-based instruments) and a host plug-ins/effects.
In short, RAM is you repeating info in your head as you’re going to write it down on paper (hard drive).
Hard Drive Storage: 100GB and above… Most PC’s come with at least 80GB of storage. One thing to note, most of the time files are recorded in a “Raw audio format” (i.e. .wav or .aiff ) which tends to be rather large so file space adds up

.
Two things to keep in mind with dealing with storage;
1) The speed of the drive needs to be at least 7200 RPM.
2) Using separate hard drives.
The first drive, typically the C: drive can house the OS and programs. The second drive can house the audio/plug-ins/samples. You may even want to have a third drive if you tend to get sample heavy and like to back things up.
The main reason you would want multiple drives, if your main drive fails (OS crash, virus, old age, faulty) then you don’t want to lose your work, and then using a drive for backup is always critical you never know when your audio drive may be called to yonder.
CPU/ Processor: At least 2.0GHZ. When it comes to processing multiple tracks and handling (VST) / munching through data, the more the better. The higher the GHZ the more brain power when it comes to think/multi-tasking and such.
Audio (Sound) Card/Interface: Basically this where the sound is generated (output) or recorded (input).
They can come integrated with the motherboard/CPU or inernally based connected to a variety of ports, such as, Peripheral Component Interconnect (PCI) or the newer PCIe(e for express) and the elder statesman, Small Computer System Interface or ( SCSI
pronounced skuzzy).
You can also get an Audio Interface externally.
Digidesign’s Mbox, Presonus FireBox, Mackie’s Satellite Onyx and the list goes on. (
M-Audio, MOTU and etc...) these are connected via USB 2.0 or Firewire.
Unless you are buying a music built computer, the sound card that comes with your computer is typically a crappy one. Especially when it comes down to solid “head turning” quality recordings. Also the “stock sound card” probably doesn't come with the appropriate inputs (1/4th in., RCA, or XLR ) for you to properly record with.
However, you can always hit up Radio Shack to get some 1/4th to 1/8th converter for your Line in or mic jacks. With the converters, you may still be able to get some decent recordings.
So if you already have these things in place, then you have to deal with setup... "which is more funner"... lol
Hope this helps, pardon the English...typing fast and i'm sleepy...