Your PC is bristling with ports, sockets, lights and buttons, but what do they all do? Putting a bit of time aside to find out the exact function of all the connections and spare slots your PC has to offer can unlock some real potential you never knew existed.

This feature will explain in simple terms exactly what those sockets, plugs and chips are there for so that you know what to ignore and what to tinker with to make your own hardware upgrades and exploit your PC's full potential.

Drive bays
Your PC's 5.25inch drive bays house optical drives such as DVD-ROM or CD-RW drives. On the front of the drive there's usually a button to open and close the drive drawer and perhaps a volume control.

Smaller 3.5inch drive bays usually accommodate the floppy disk drive, although there are all sorts of weird and wonderful peripherals available these days that fit into these bays. Most common is a memory card reader that allows you to transfer image and MP3 files onto your PC from a variety of memory storage cards.

Power and reset button
There are usually two buttons on the front of your PC. The main power button is only used for turning the PC on, although if your computer is running Windows XP you can configure the button to also turn off your PC, too.

The other button is usually slightly recessed. This is the reset switch and is handy for restarting your PC if it crashes.

Lights
On the front of your PC are a number of LEDs. These usually indicate two things: hard disk activity and power. However, there may be any number of other lights which can be either decorative or indicate a variety of other functions.

The lights on your PC can generally be ignored but there is one golden rule: never unplug your PC if the hard disk light is lit as this could lead to loss of data, or even damage the hard disk.

Front ports
Older PCs don't tend to have any connectors on the front of the case but most PCs built recently have two or more USB ports situated on the front of the case to allow you to connect devices easily. The sockets are often hidden under a flap to improve the PC's appearance.

Power socket and power unit
The large, black rectangular socket on the rear of your PC is the main power connector and is integrated into the power supply unit. Make sure the isolation switch located next to the socket is switched on after you have connected the power supply cable to your PC.

Motherboard back plate connector
On the rear of your PC are all the connections you need to attach your keyboard and mouse, internet connection, printer, USB devices and audio connections. All these sockets are attached to the motherboard of your PC and are colour coded to help you match up the right socket with the right plug.

Expansion card ports
These connectors protrude from expansion cards installed inside the computer (see below for more about these). Your PC is likely to be fitted with one or more of these expansion cards, which are added to give your system fancy graphics or sound facilities.

Case screws and fixings
On the side of your hard disk and optical drives you'll find screw fixings. These fixings enable you to securely fix the drives to the inside of the PC case. These help both to reduce any noise caused by vibration and to prevent the drives from moving around inside the case and causing damage.

Power connectors
All the drives in your PC need power. This is supplied by the main power supply unit positioned at the top of the case. On the rear of your drives will be a white oblong power connector, connected by a power lead to the power supply unit inside the PC.

There are several different types of power connectors inside your PC; most will be of the type we've just described but there will also be some smaller ones such as the connector that attaches to your floppy disk.

Hard disk
The hard disk is the long-term memory of your PC and is a small rectangular box that plugs into an IDE socket on the motherboard. Hard disk capacity is measured in gigabytes and most modern hard disks have a capacity of more than 20Gb.

All the files that you create and the software you install will be stored on the hard disk. Hard disks today allow you to store a vast amount of information but if you run out of room it's reasonably easy to fit a larger or additional hard disk.

Graphics card
This sits in the AGP slot on the motherboard and allows your PC to produce the graphics that appear on screen. See below for more information.

Processor socket and cooler
The processor is the brain of your PC and performs all the calculations and number-crunching involved in running Windows and other software. The processor is obscured by the fan and cooler fixed on top. Processors generate a lot of heat and need to be well cooled to prevent then from overheating and burning out.

Dimm slot
These slots hold Ram (Random Access Memory) modules. See below for more information.

PCI slots
PCI slots are the oblong slots on the motherboard that allow you to add hardware to your PC and extend its capabilities. You will already have at least one PCI card in your PC, usually a sound card or modem, and there will be one or two extra slots which allow you to add any other PCI cards you might need such as a FireWire card.

IDE connector
The IDE sockets on your motherboard are connected to the back of the hard disk and optical drives using a long, flat 'ribbon' cable.

The IDE channels carry all the information to and from long-term storage devices like hard disks and optical drives. There is a minimum of two IDE sockets inside your PC and you can attach two devices to each one.

Memory
Ram (Random Access Memory) is the short-term memory of your PC. These memory chips or 'modules' are slotted into the motherboard. When running applications, your PC needs this fast, short-term memory as the hard disk isn't quick enough to cope with the amount of information being transferred.

Generally speaking, the more Ram you have the better your PC will perform overall. To fit memory into a slot, make sure the recesses along the edge of the chip correspond with the memory slots on the motherboard. Place the memory module into the slot and press down until the retaining clips move into place at either end and grip the module.

Accelerated Graphics Port
AGP is a standard which was introduced some years ago to allow graphics card manufacturers to produce high-performance cards for games. The connectors are usually dark brown and are located next to the PCI slots on the motherboard.

Fitting AGP graphics cards can be a little tricky because they tend to be quite large and the AGP sockets often have an extra clip that grips the card to the connector. Always read the instructions provided with any hardware before you attempt to fit it.