Lift the lid on your PC

Do you know the difference between memory chips and motherboards? Gary Marshall, author of a new Haynes manual, reveals how to boost your computer's brainpower

Processor

What does it do? The processor is the engine – or brain – of your computer, and has a huge influence on how fast it is.

How easy is it to upgrade?

The processor sits beneath the fan, plugged into the motherboard. To replace it you must take the fan off first, so it can take a while.

How much does an upgrade cost? Anywhere from £30 for an Intel Celeron to £600-plus for the latest Intel Quad Core Extreme. If you know your way around the inside of a computer, save money by buying an OEM (original equipment manufacturer) version. This will come with no instructions or technical support – just a processor chip in a box – but it'll be half the price.

Is it worth the hassle?

It's a similar proposition to replacing a motherboard – you may find that other parts of your PC are not compatible with the new processor, so it can get very fiddly. But if the processor has broken, you might want to do a straight replacement. Most people will be better off buying a whole new computer.

Motherboard

What does it do? All the key components – RAM, processor and graphics card – are plugged into the motherboard.

How easy is it to upgrade?

Changing the motherboard is the most complicated thing you can do with your computer, as it involves unplugging everything, taking it all out, and then putting it all back together again. It's very time-consuming and fiddly.

How much does an upgrade cost? Provided that your other bits and pieces are compatible with the new motherboard, it shouldn't cost too much – somewhere between £40 and £80. However, the chances are that they won't all work together – each motherboard has its own memory and hard disk requirements. By replacing your motherboard, you might end up having to replace the processor, RAM and other components, and that could cost a fortune.

Is it worth the hassle?

No. You might consider this if you're planning to keep your case, throw everything else out and build a new computer from scratch, or if you've broken the existing motherboard and want an exact replacement. In most other cases, you're better off buying a new computer.

Disk drive

What does it do? CD-RW and DVD-RW drives play and burn CDs and DVDs. They're almost standard with new models, but older computers may only have the ability to read, not record, disks, so you might want to replace the card.

How easy is it to upgrade?

It's straightforward – as long as you buy the right thing. You just unplug the wire at the back of your existing drive, slide it out, then slide the new one in and plug the same wire into the back. Make sure you call the manufacturer before you buy to check the new drive is compatible.

How much does an upgrade cost? Not much. You can pick up a CD/DVD drive and CD writer for about £22 from sites such as www.dabs.com.

Is it worth the hassle?

This really depends on what you're using your computer for. If you want to burn CDs or DVDs and your current computer doesn't let you, then it's certainly worth the small expense.

RAM

What does it do? The thinking power of your computer is the Random Access Memory. Everything your computer does is held in this memory, so if your machine struggles and slows down when you try and run several programmes at once, you almost certainly need to upgrade.

How easy is it to upgrade?

Installing extra memory is no more difficult than putting your cash card into an ATM machine – you simply have to push the card into a slot. The difficult part is making sure you buy the right upgrade. Check out the upgrade adviser on www.crucial.com, which will scan your system, tell you what is in there already and what you can buy to make it work faster.

How much does an upgrade cost? Crucial also sells RAM cheaply. One gigabyte (1GB) should not cost more than £50 to £100.

Is it worth the hassle?

This is the best thing you can do to improve your computer. Upgrade to at least 512MB (that's half a gigabite) if you're using Windows XP, while 1GB is essential if you use the memory-guzzling Windows Vista.

Graphics or video card

What does it do? It's an expansion card with dedicated RAM for generating images on the screen. Cheaper computers without them can be painfully slow running games – add one and it should make things faster.

How easy is it to upgrade?

It slots straight into the motherboard – though you may need to use a reasonable amount of force. Always be wary of static electricity when opening up your computer; do try not to wear a shell-suit, and buy an anti-static wristband. A little spark could wipe out a memory card.

How much does an upgrade cost? You could pay up to £400, although this is wasted money unless you're using it with a really fast processor. For most games fanatics, a 256MB card for between £30 and £50 will give you plenty of oomph.

Is it worth the hassle?

If you're into games, this could be your best investment. Windows Vista is also quite heavy on the graphics – if you want to use the whizzy interface, then you'll need a graphics card with at least 128MB of RAM.

Sound card

What does it do? This lets you hear cinema-quality sound. If your computer's fairly old, a sound card should let you get decent surround-sound when you hook it up to the right sort of speakers.

How easy is it to upgrade?

Phone the company that sold you the computer so they can advise you which card will work. As with a graphics card, there's a slot on your motherboard – one firm shove and you're away. If you have a laptop, it's best to use an external card that plugs into a USB socket.

How much does an upgrade cost? From £30. www.creative.com sells a range of laptop audio add-ons that plug into your USB port and offer surround sound. Other sound cards for desktops allow you to plug in a keyboard or guitar.

Is it worth the hassle? It can be, but not before you've tried using better speakers – particularly you're currently using the freebies that came with the machine. There's no point putting a better sound card in if you're still playing music through a couple of tin cans.

Hard disk

What does it do? The hard disk is where everything in your computer lives: software, documents, photos, films and music. The bigger the hard disk, the more you can store.

How easy is it to upgrade?

This is one of the easiest things to upgrade on your computer. One approach is to buy an external hard drive. This is a separate box that sits next to your computer – plug it into a USB socket and you're away. A neater option is to replace the hard drive inside your machine. To make sure you're buying the right thing, call the manufacturer of your computer.

How much does an upgrade cost? You'll save around 30 per cent off the high street price – sometimes a lot more – by buying online. The website www.dabs.com is an excellent site for internal and removable hard disks – a 160GB disk costs just £35.99.

Is it worth the hassle?

A handy upgrade if your photo albums or iTunes downloads are growing out of control, and it's one of the cheaper ways of improving your computer. An external hard drive is also an excellent way of backing up files.

Wireless card

What does it do?

Lets you to access the internet via a Wi-Fi connection.

How easy is it to upgrade?

A range of external plug-ins will have internet up and running in a matter of minutes. You just plug a small box straight into a USB socket.

How much does an upgrade cost? The small key-ring-size boxes, or " dongles", that plug into a USB socket cost as little as £10. Alternatively, you could get a larger card that slots into an expansion slot at the back of your desktop PC. These are called PCI cards, and cost about £15 for a desktop PC, or £20 for a laptop.

Is it worth the hassle?

Wireless internet is incredibly handy if you have more than one computer, or if you like to take your laptop from one room to another.

Interview by Mary Ama Asamoah

Build your own Computer by Kyle MacRae & Gary Marshall is published by Haynes, £17.99. To order a copy for £16.19 (free p&p), call Independent Books Direct on 0870 079 8897 or visit www.independentbooksdirect.co.uk