In order to make music with your computer, the minimum you need is a soundcard and good software. Modern computers usually ship with a built-in soundcard already, which is sufficient to start with - just connect an amplifier or headphones to it. Nearly all soundcards have Mic In/Line in connectors as well, so if you wish to record vocals or instruments, you only need to purchase a microphone and connect that. Although some soundcards come bundled with a microphone already, those are usually of poor quality and not suitable for decent music production. Thus a good idea here is to seek advice in your local music store.

Next you need to find good music software. Fortunately there is a lot of applications available for all common computer platforms, no matter if you are using Windows, Linux or Mac OS X. To find good applications for your platform, type something like "Music Software for PC" into your favourite search engine.

A good idea is to start with free software, then move on to commercial software once you got the hang of it and your requirements grow. You might also want to look at the applications that are given away for free on cover CDs of music magazines, or those that come bundled with your soundcard. Some music software developers give away older, discontinued or feature-limited versions of their software for free. Often such software is a lot more capable than software which has always been distributed freely.