If your PC is showing its age, or you are thinking of taking an old office machine home, here are 10 ways of giving it a midlife pick- me-up. Some are easier than others, some more expensive but all are manageable with a little application. In our DIY rating, 1/10 means a child could do it, while 10/10 means you can do it only with a team of engineers at your elbow.

By the way, if you have an Apple Macintosh, adding new bits to your machine tends to be easier than with a PC as nine times out of 10 the Mac will automatically configure them. Windows 95, with its similar "Plug and Play" facility, has made the PC a lot easier to upgrade but there can still be problems. Older PCs don't normally support Plug and Play even if you are running Windows 95, although the operating system will try to help you configure new devices.

Similarly, new computer boards and peripherals that do not meet the Plug and Play standard (and there are many) will again not be recognised by Windows 95. If you do not have plug and play, you will have to configure software and, probably, flick with tiny switches: not necessarily difficult, but fiddly.

Processor upgrade DIY rating: 4/10

Most 486 machines have a socket into which you can simply slip a more powerful processor. A 486 33SX (the 33 stands for 33 megahertz) will convert to 100 DX4 for pounds 100-pounds 130. This represents a 70 per cent increase in processor power (but don't forget other parts of your old PC will slow you down.) On some 486 machines you can go zooming up to a Pentium. You can convert a 33SX to an 83MHz Pentium for the same price.

Sadly, 286 and 386 machines are not upgradable. There are upgrades for earlier Pentium models but they are pricey. To boost a Pentium 60 or 66 up to a Pentium 120/133 will cost around pounds 270. You can even get an upgrade chip for the comparatively recently released Pentium 100.

For Macintosh users there is the Power Macintosh Upgrade Card, the Macintosh Processor Upgrade Card or the Power Mac Logic Board Upgrade. The first can be installed in most 68040 Macs yourself. The other two must be performed by an engineer. These upgrades cost around pounds 450.

Check carefully with your PC manufacturer which upgrade chips will work. Processor upgrades are quite easy to do yourself, but you can hit problems, so do this when you know the telephone helplines are open.

Extra memory 4/10

One of the best investments is extra memory for your PC. If you are running Windows 3.1 on 4 MB or less, an extra 4 MB will make a huge difference. Users running Windows 95 on 8 MB really should upgrade to 16 MB at least. This could give you a 30 per cent or 50 per cent increase in performance. 8 MB of memory will set you back around pounds 150. upgrading is normally a straightforward process, but check you are buying the right sort of memory for your machine.

New hard disc 5/10

If your hard disc is filling up, how about a new hard disc? They are easy to fit. If your machine is a couple of years old, you should make the new disk your main disc as it is likely to be much faster than your old one. A 1 gigabytes (1,000 megabytes) disc can cost less than pounds 150, 2 GB less than pounds 250.

Fitting is not easy. You have to locate a couple of wires and undo a few screws. The biggest problems come with configuring the system. Ring the makers support desk if you have problems.

External disc drive 1/10

A quick fix for your overloaded hard disk is an external disc unit. Best known is the Omega ZIP drive. The drive, which just plugs into the parallel port on the back of the PC costs pounds 150 with blank 100 MB discs costing around pounds 12. Excellent for sharing data between office and home machines although much slower than a hard disk.

Faster modem 2/10 (external); 3/10 (internal)

If you are struggling with an old modem check out the speed. If you are not using a 14.4 kbps or a 28.8 kbps modem throw it in the bin. 28.8 modems cost around pounds 160 but prices are dropping fast: 14.4 modems cost pounds 90 or so.

Most modems are, physically, easy to install. Configuring all your software to take full advantage of the new power, however, may take a while. Well worthwhile if you are still soldiering on with an old 2,400 bps or 1,200 modem.

Better monitor 2/10

If you are still using a VGA monitor, a jump up to a Super VGA or better monitor will make Windows applications easier to view. Several companies do monitors with integrated speakers and microphone which, if you are going down the multimedia path, make for a very tidy desk.

These are easy to install but check with the manufacturer that your video card will be able to drive the higher resolutions on the monitor. You may need a new video card, too. If you don't, plug in the monitor, perhaps adjust a setting or two to get the best from it and there you are.

CD-Rom drive 2/10 (external); 4/10 (internal)

If you have an old single-speed drive, a quad or six speed drive will cost you only pounds 50-60 and will revolutionise your use of CD-Roms. External drives are pretty easy, internal drives not as difficult as installing a hard disc but more trouble than a modem. But certainly well worth doing.

Sound system upgrade plus speakers 2/10

If you want to play with interactive titles, it can be worth upgrading your sound system to get rid the tinny sound of cheap cards and speakers. A wave table or other 32-bit sound system will give you almost CD-quality sound for pounds 120-150. A pair of good computer speakers will also make all the difference, price pounds 12-pounds 200.

Installing the sound card in your PC is not difficult. Changing settings for the card, and for your existing software, as well as the setting in all your existing software that use sound can be a bit of a chore. Plugging in the speakers, you will be pleased to know, is simplicity itself.

New printer 2/10

Most people will only see your work on the paper you send them. A good printer will make your business look that much more impressive and it should be quite straightforward to fit.

Scanner 2/10

If you want to make an impression, get a scanner. This will let you take any image into your PC. Even a black and white scanner can be fun. Costing from pounds 60 to 600, scanners come in many different forms. The best are flat- bed scanners, but they are expensive and take up a lot of space.