Buying a PC is a big decision - for a start it's one of the most expensive electronic devices most consumers are likely to purchase, with only specialised home cinema and audiophile equipment tipping the bar at much over the £1,000-ish outlay required for a new desktop computer. Investing in one also needs careful consideration and lots of research. Computers are complex machines to understand - particularly for first-time buyers - and no one wants to spend a grand only to end up with a big, beige paperweight.

Thankfully, there's no shortage of buying advice available to guide consumers through the minefield of system specifications and different makes and models. And to better understand the hardware aspect of computers and keep up to date with many of the latest desktop and notebook models, turn to the pages of our sister publication, Computeractive magazine.

In this feature, meanwhile, we'll touch on some of the things you should look out for when buying a PC generally, but with a specific focus on the sorts of points you'll need to think about if you decide to make your purchase from a website or online vendor.

We'll examine what you should be looking for in your new system or supplier, where you are most likely to find a good online outlet, and whether you can entrust such an important purchase to the vagaries of cyberspace. We will also look at whether or not you can save money by shopping for computers on the net, as well as why you shouldn't trust everything that looks like a bargain.

An informed decision
PC's are incredibly flexible machines that can be put to any number of complicated and demanding tasks. But having some kind of idea about how you'll actually be using yours will help a great help when it comes to choosing the right one and, to a certain extent, govern where you should buy it from and how much to spend. So, ask yourself this: what will you be doing with your computer? Playing the latest 3D games? Emailing and word processing? Digital photo editing? Or perhaps a bit of everything?

If, for instance, you have no interest in playing computer games, you can make an instant saving by opting for a cheaper graphics card. You can't do without one altogether, but opting for a computer without the latest high-powered graphics card means that you can blow the money on something you need more - extra Ram or a bigger hard drive, for instance.

You'll also need to consider a wide range of other factors that directly affect your choice of make and model. Do you need a desktop PC or might a laptop be more suitable? Do you need a large monitor in order to work with your PC effectively? And, most importantly, how much are you prepared to spend?

Nothing encourages overspending like buying a PC; you can easily double your budget by going for the system you'd like to own rather than the one you actually need. You'll have to strike a balance between buying a system that's built to last and one that's overly expensive because it's made up of all the very latest components. There's no point in paying for things you're not really going to use, but it would be equally as pointless to buy a system on the merits of its price alone.

Build it yourself
If you decide to buy your new PC over the counter at your local computer superstore or high street electronics retailer, much of the true decision-making is taken out of your hands. By and large, off-the-shelf computers are pre-built and pre-configured to strict specifications that have been decided on by the manufacturer. There's nothing wrong with buying the latest Packard Bell or Advent system from your nearest computer shop but, if you really want to fine-tune your computer to your needs before you buy it, you should consider buying online.

Many of the best computer manufacturers, such as Dell and Mesh use the unique interactivity offered by the web to allow you to pre-configure your own system. Head to the websites for companies like this and you can play around with different combinations of key components - a bit more memory here, a different DVD drive there - effectively allowing you to tailor your new computer so that it suits your budget and your needs down to the ground.

This way of shopping also allows you to make some keen value comparisons - put together your dream computer at one manufacturer's site, then go and see how much a similar system would cost at a competitor's online outlet. Compare the prices of PCs offered by online vendors with off-the-peg computers and you'll notice a fairly sizeable saving, too - with estimated price differences of up to 10 per cent.

Computer manufacturers that sell directly through the web rather than in physical stores have fewer overheads to contend with, and are often able to pass on their savings to their customers in the shape of lower prices. Online vendors also tend to use newer components than pre-built computer manufacturers and are able to more quickly adjust their prices to reflect the latest wholesale cost savings in the ever-changing electronics market.

Freebies
Due to the fierce competition in the computer hardware market, you might find that comparing prices for the same sort of system at a range of different online outlets might result in only minor price differentials. If that's the case, then you should look carefully at any added-value aspects, freebies and special offers that each manufacturer is proposing, to see if any of them work in your favour.

Most PCs come with bundled accessories and software packages to tempt the passing punter, and they present buyers with both risk and opportunity. Every free printer, scanner, webcam or software suite offered will probably be paid for by a deficiency elsewhere in the specification. Also, the 'added value' products might not be up to much. Digital photographers might, for example, find that they are disappointed by the results they get from their free inkjet printer, and end up having to make a separate purchase for a better one anyway.

On the plus side, some online sales incentives are genuinely useful - doubling your Ram for free, for instance - and many online vendors allow you to barter, so it might be possible to swap a useless freebie for something far more valuable, such as a faster processor or a larger screen.

When bartering with retailers, however, it's worth noting that speaking to a sales representative face to face or calling the sales hotline can often prove a lot more productive than using online forms or email.

The special offers tendered by web-based computer sellers also have a tendency to change on a surprisingly frequent rota. One week it might be a useless free joystick and the next it might be a bargain deal on extra memory, so it's worth going back and checking with each site regularly.

In the long run
Naturally, there is no shortage of web-based companies prepared to sell you a PC, and the slickest ones will bend over backwards to get your business. The deals and freebies they offer to try to get your attention are not, however, the true test of their value - that comes when something goes wrong, and here's where some clever shopping can simultaneously save you some cash, and buy you some piece of mind.

Many companies will try to flog you five-year warranties. That might sound comforting to anyone intimidated by the complexity and cost of the equipment they are buying, but extended warranties can be deceptive, and it's crucial to look at the terms and conditions that are offered. The first year's cover is usually the most important, so make sure that you have got at least 12-months' on-site warranty, which means that the manufacturers will come to your home to collect or fix the computer.

Also worth factoring in are things such as the cost of telephone support, since most computer troubles are software based and can usually be sorted out on the phone. Compare manufacturers and pick a company that has long helpline hours and cheap telephone rates - we guarantee that you will really appreciate it later on, should the worst happen and something goes wrong with your system.

Buy it!
Once you have narrowed down your choice, it's time to re-check all the details. You need, for example, a confirmation of the final price of your system (including 'hidden' costs, such as VAT, delivery and warranty) and a delivery date. Over the counter, these sorts of things are rarely an issue, but when you're buying online, using a phone sales line or email, make sure you get confirmation of these things before you commit to buying. It also provides one last chance to haggle.

This is a good time to do one final bit of homework. Do a web search on the companies you are planning to do business with. Notice any long list of complaints or angry user-forums? If so, move on to the next supplier.

When you have made your choice, confirm your purchase, making sure that any online payment forms are secure (look for the 'https' at the beginning of the URL), and using a credit card for added consumer security. Congratulations - the easy part's over!

What if it goes wrong?
Whether you buy a PC online or off the shelf, there's always a slim possibility that things might not always go as smoothly as you would like - especially with such technically demanding products as computer systems. So what do you do if your PC doesn't arrive on time, doesn't work properly, or breaks down entirely after a couple of days?

Fortunately, your consumer rights are strongest during these first few days. For a start, according to EU legislation, you have a seven to 14-day cooling-off period - when you can cancel your order at any time (provided the goods are not already dispatched, in which case it is your responsibility to return them).

Furthermore, all orders have to be sent within 30 days and, once again, you can cancel if this is not the case. Finally, all goods must be suitable for the purpose for which you ordered them. So, if the system you receive does not meet your expectations, you may have the right to swap it for something else. Naturally, the sooner you spot any problems or anomalies the better.

Generally speaking, your consumer rights are the same when buying online as they are in the high street. For a fuller explanation of how the law works for you, see the DTI website at www.dti.gov.uk/consumer_web.

Conclusion
There are, of course, a few drawbacks relating to buying a PC online, but most shoppers will find that the benefits far outweigh the disadvantages. And you can continue to reap the benefits of the lower costs of online shopping well after your new PC has been delivered by purchasing all your upgrades, peripherals and consumables from the net, too. Have a look at the prices at Dabs, for example, or use an online price comparison service such as Pricerunner to track down what you want at the cheapest price.

PC buying online
There are hundreds of sites for web-based computer vendors, and it's always worth shopping around to compare prices and after-sales benefits. Here are five slightly different approaches to online computer sales.

Dell
www.dell.co.uk
One of the first e-commerce sites and as slick and user friendly as you could wish. Dell has never been the cheapest, but does have a reputation for reliability and customer support. The site is child's play to use too.

Mesh
www.meshcomputers.com
Best known for systems that cram in as many brand new components as possible at reasonable prices, the Mesh website is a tad confusing at first. However, online ordering is reliable, telephone support helpful, and upgrade bargains are plentiful.

PC World
www.pcworld.co.uk
Unlike many of its competitors, this big high street name has a fairly good website to back it up. Browse till you find what you like, then either order online or hop in the car and pick it up at your nearest branch - a store locator is also provided on the site.

CEX
www.cex.co.uk
For value, Computer Exchange is hard to beat. OK, the systems tend to look well used (often because they are) but all second-hand goods are covered by a 12-month guarantee. And, at £500 for a 3GHz system, a pre-owned computer is certainly worth consideration. A small selection of offers can be found online, but to buy or sell you will need to visit one of their dozen or so stores.

eBay
www.ebay.co.uk
At eBay (or any other auction website) you are buying second-hand goods from private vendors with all the risks that this entails. Certainly, there are bargains to be found, but remember to factor in delivery charges, surcharges for using PayPal or insurance costs - and bear in mind the absence of any meaningful guarantee.