Upgrade your RAM. If you want to use your PC for multi-track recording or other demanding music tasks, you will need to ensure that you have enough memory to render all of the necessary commands in real time. Purchase an additional RAM card for your PC and install it for improved performance. If possible, try to use the maximum RAM that your computer will allow.
Connect an audio interface. Audio interfaces are just external sound cards designed to accommodate PC music configurations. Whether you want to connect instruments and microphones for recording or just connect stereo speakers for music playback, an interface contains all of the jacks you need to connect instrumentation, tape decks, turntables, monitor headphones, speakers, amplifiers and stage boxes to your PC, and requires only the use of one USB (or in some cases, FireWire) port. You can compare audio interfaces at most music supply stores.
Install your audio interface software using the included CD-ROM and configure the interface using your control panels. If using Mac OS X, open your "System Preferences" (accessible from the Apple menu at the top of your screen), select "Sound" and select the interface as your input and/or output source. When using Windows, open your "Control Panels" (accessible from the Start menu), select your "Sound" panel (found on the Appearance control panel, in some versions) and select the device as your input and/or output source. If you plan to record music, select the interface as your input device. For stereo playback, select it as your output device.
Install the needed software. For music recording, you may want to download a professional multi-track recording program like Audition, Cubase, Reason, Logic Pro or Pro Tools. For cheaper or free alternatives, try Audacity, QTractor or LMMS (see Resources). If you want to designate your computer for music playback rather than recording, you will need a media player like iTunes, Media Monkey, Winamp or Windows Media Player (see Resources).