There are three ways you can acquire a computer for music; buy one from a high street or online retailer off-the-shelf, build your own, or get one from a specialist supplier of computers specifically designed for audio. Let's take a look at the pros and cons of each:
High street computer suppliers are unlikely to know anything about professional music software or hardware. The computers they sell are designed and tested for regular home applications such as games, internet browsing, office software and entertainment. On paper there is often no reason that these machines can't cope with professional music software and hardware. However in reality, although marketed as all singing / all dancing, they often struggle in terms of compatibility and power, lacking in areas that are important to musicians. Typical problems are slow hard drive speeds, stacks of pre-installed software that uses up valuable resources or causes conflicts, and cut down motherboards that cause hardware compatibility issues. On the other hand, if you're prepared to spend a little more, then you can pick up a decent, well-specified computer for a reasonable price and set about installing the music software and hardware yourself. If you run into trouble though, then things can get difficult. They are unlikely to be able to help you solve compatibility or installation issues, and experience has shown that they will often blame your third party hardware or software, rather than their computer.
Roll Your Own
If you are on a very tight budget, or just a plain tech-nerd, then building a computer can be a worthwhile exercise that make you more familiar with the technology involved in running a system. It's not simple, but it's not too difficult either - with a good dose of common sense and plenty of time set aside, it's a perfectly valid option. The hardest part is choosing the components. A good trick is to check out some of the specialist suppliers of music computers (see below), and 'steal' their specifications. Another tip is to hang out on music technology forums - chat to other people about what they use and recommend. The financial can be large, however the cost in terms of time spent getting the system up and running can also be larger! You'll end up with a system that you know intimately, but you'll also be the only person you can call if it goes wrong. One of the main reasons people choose this route is to be able to specify the machine exactly, from the size of the case to the number of drive ports and PCI slots.
Once the machine is physically assembled, you also have to consider the installation of Windows, and getting that working correctly with your music software and hardware - not always a simple process. But with perseverance and patience, you can put together a very powerful system for a great price, and once you've mastered your first one, then your next upgrade should be a piece of cake by comparison.
The third option is to get your system from a company that purports to know what they are talking about in terms of music and computers, but check out the forums to get the low-down on who really does! The advantages are that they will provide you with a fully working and tested computer, purpose-designed for music production. The component choices are all made for you, all you have to do is choose 'good', 'better' or 'best' from their menu according to your budget. And budget is the biggest problem - specialist systems are generally quite expensive when considered on spec's alone. These companies are usually small outfits that are not able to buy components in huge quantities, and so their pricing isn't as competitive as the large high street retailers. Additionally, they take a lot of time testing and installing the systems to ensure that everything is running perfectly, and you are also buying into the confidence that if you have trouble with your system, they will be able to support you and resolve your problems. Specialist systems tend to be high-end and high performance, with quality components and knowledgeable support. They can be pricey, but they are usually worth it, both in terms of peace of mind, and in getting a system that is fit for purpose.