More power without getting fleeced:Today's high-powered software may make your old computer look like something out of the Ark, but as this four-page guide shows, you can extend its life without breaking the bank

A new PC could cost pounds 2,000, but there are hundreds of ways to update your old one, says Andrew Orlowski

A car will last 10 years, maybe more, so why doesn't a computer? Unlike fatigue-prone iron, software doesn't rust - a word-processing program will be as good as the day it was released. But the sad truth is that after you have had your personal computer for a year or two, you will notice that your terminal can no longer run the latest software. And after three or four years, you may well be apologising that your equipment is "out of the Ark".

The villain is the increasing "girth" of software. The bells and whistles on modern programs - automatic spelling correction, fancy graphics and so on - take up enormous amounts of disk space and memory. Windows 95, for example, will not even fit on a 40-megabyte hard disk that would have been standard three years ago.

The easy way to cope with "fat software" is to buy a new machine. If you switch from, say, a 386 to the latest Pentium PC, you will find you don't just have a faster processor, but also a whole bedrock of improvements giving better video and throughput, as well as Plug and Play. The bad news is that you will probably have spent the best part of pounds 2,000, and your original investment will have been trashed. You won't be able to take much of your old machine with you.

This is why an upgrade could be the answer. There are hundreds of ways to increase the capacity or speed of a computer, using hardware or software.

The original personal computer was cobbled together by IBM from off-the- shelf parts. Unlike the Apple Macintosh (see page 12), it was not designed to be a household appliance. Nor did IBM employ a team of dedicated designers to create the hardware and software, as Amiga did. The most serious effect for the potential upgrader is that unless you have Windows 95, you will not have Plug and Play. This allows the system automatically to recognise its own "limbs", or peripherals - if you add a new hard disk to a Mac, it will immediately accept it. With a PC, you have to "tell" the computer about it, using the jargon of I/O addresses, IRQs and jumper settings.

Most of this special report is about hardware upgrades. Unless you have Plug and Play, the golden rule is to buy a kit that has step-by-step instructions. Although the physical installation process may be simple, a new device will not work unless the correct adjustments have been made. It is, of course, possible to have a shop or specialist company fit your upgrade for you - see page 10.

A couple of years ago, software upgrades were all the rage, and they avoid the plug and play problem. But they are a short-term solution. The hardware rarely runs any faster - all that happens is that the software improves performance in one area at the expense of another.

For example, disk doublers such as Stacker have enduring appeal. The software creates a large compressed file on a disk, giving additional hard-disk space. This wizardry comes at a price, however, as the processor has more work to do squeezing data into the compressed area: the system is slowed down by 15 per cent on average. Although still popular, disk doubling software has become less attractive because the price of large hard disks has fallen by 75 per cent in the past couple of years. That means a new hard disk can be cheaper than the software.

"Memory doublers" also have their followers, despite only marginal performance improvements. This software claims to improve the efficiency of the memory in use - although a recent bestseller, SoftRam, was withdrawn after tests found it failed to bring any benefit.

More useful may be some judicious tinkering, or more careful use of existing resources. Windows 3.1's performance can be improved by fiddling with the obscure settings that your manual either does not tell you about, or documents poorly. Buying Microsoft's own Resource Kit book and CD could be a good investment, or consulting one of the on-line "Frequently Asked Questions", a compilation of tips to be found in the Windows newsgroups on the Internet (for example, comp.os.ms-windows.setup). Enabling one small option - such as 32-bit File Access - can bring dramatic improvements.

The popularity of easy-to-use "advice" software such as WinProbe or First Aid for Windows illustrates that such tweaks are of value. With these utilities, many of the bottlenecks on a low-end machine that might prevent, for example, Word (a wordprocessor) and Excel (a spreadsheet) running together can be alleviated.