One of the problems with today's personal computers is that they don't come with a yellow plastic briefcase, or even the sticky labels and bottle of Tippex that are so important to long-term satisfaction. But if you are just unwrapping a new computer, now is the time to remedy these defects. And if you have had a machine for years, you may still be able to rescue it.

Today, hardly any long-standing home computer user has the answers to life's tough questions, such as: Where is the Start Here leaflet for that CD-Rewriter? Where is the PC Pro cover disc you used to load a utility program three years ago? Where is the floppy with the original drivers for your sound card? And where are the case locking keys you never used?

In every case, I know the answer. They are in the yellow plastic briefcase under my computer trolley.

It does not have to be yellow or plastic, but it should be cheap and fairly sturdy. The point is that you need somewhere handy to put all the disks, manuals and odd bits of stuff that are essential to run - or to rescue - your machine. If the hard drive fails, you should be able to take out the case and reinstall everything, both from back-up discs and from scratch. One day you will be grateful not to have to hunt for any of this stuff in the loft.

The other thing you need before you start is a decent mains extension cable with eight three-pin sockets. You may think you only need to plug in two or three things - computer, monitor, printer or whatever - but in the long run you will need more. Modems, external drives, scanners, handheld computers, mobile phones, battery chargers and other peripherals often need to be plugged into the mains, and you will need somewhere close to the PC to plug them in.

I use a Belkin SurgeMaster II, bought from Dixons, which also provides protection from mains power surges and lightning strikes, plus in and out sockets for telephone and AV cables. Lightning may not strike often, but I'm ready for it.

Putting a PC together is, these days, a simple job. If your supplier is competent, all the cables will be colour coded, so it should be obvious what goes where. (You may have to squint a bit.) However, it is not always obvious which way up the connectors fit. I solve this problem by putting a small dab of Tippex on the side that goes on top.

Another useful tip is to label the mains plugs, which is where the sticky labels come in. Get the power cable for the system box, label the mains plug, and write CPU on it in big, bold letters. Label the other plugs SCR, PR, MOD or whatever. When your computer wiring looks like three plates of spaghetti - and it will - and you are on your knees wondering which plug to pull, you will be glad you did.

Finally, there's the question of packaging: you should keep it, though you can fold the boxes flat. If the worst comes to the worst, the machine may have to be packed up and returned to the manufacturer, and without the original packaging, you will be stuck. Even if the machine works perfectly, you may still need the boxes if you sell the computer in years to come.

Software

Once you have the hardware plugged in, you can organise the software. This part has three stages: organising the hard drive; installing extra software; and taking a back-up.

Most computers nowadays come with one huge hard drive (C:). I prefer to have it partitioned three ways to have sections for the operating system and utilities (C: ), applications (D:) and data (E:). You don't need to reformat your system to do this: just organise things in similar subdirectories.

If you have bought a Windows PC, Microsoft has made a gesture in the right direction. There are folders called My Documents and Program Files for data and applications. It is a good idea to use them, and it is a shame Microsoft sometimes doesn't. However, it is possible to get most applications to use these directories. For example, I have set up Outlook Express email to use a My Mail directory inside My Documents.

Having all your data in one place makes it easier to back up, and ideally, easier to back up to just one CD. If you have thousands of MP3 files, however, this will not be possible. Instead, you should store those in a separate directory - call it My Music, perhaps. Create more subdirectories when any directory grows beyond the capacity of a CD-R disc: 650 megabytes.

If you are upgrading from an old PC, you will want to move some software, settings and data across. XP provides a wizard to transfer settings on disk, while Alohabob's PC Relocator - available from Amazon.co.uk - will move many or all the things you need using a cable connector, supplied. You can also copy data across using Laplink with a Laplink cable, or Microsoft's built in Direct Cable Connection.

If you transfer things between machines by copying whole directories to a CD, remember that files on CD become read-only, and applications such as Outlook Express will not be able to use them. Go into the directory on your new PC, highlight all the files (e.g. press Ctrl-A), right-click and select Properties, untick the box marked Read-only, and click OK.

If you use the internet, you should also think about installing a firewall to keep intruders out. There are two good firewalls available free for home use: Zone Alarm (www.zonelabs.com) and Tiny's Personal Firewall (www.tinysoftware.com). If you have problems with one, the other will probably work fine.

PC users should also think seriously about installing either Roxio's GoBack 3 (www.roxio.com) or Imagine Lan's ConfigSafe (www. imaginelan.com). At some point, your system will probably go wrong, because of a bad application, a virus infection, or a simple mistake.

At that point you will want to go back to an earlier state, and that is the option GoBack provides. (A simple version of GoBack is included in Windows XP.) The only disadvantage is that it does slow the system down slightly. ConfigSafe, meanwhile, lets you take a snapshot of your PC's settings, so that you can revert to an earlier set up. What it won't do is take you back to the point before you accidentally deleted an important file, or whatever.

Backup

If the worst comes to the worst, you can always reformat - that is, wipe clean - your computer's hard drive and reinstall everything from scratch. However, this may take a day or two, depending on how much software you have installed. It would obviously be better if you could reinstall a clean back-up that also includes your main software and settings. That is what you have now, so back it up before it is too late!

Windows usually includes rudimentary back-up software, or you may already have something that has been bundled with a CD-RW or Iomega drive. For a wide range of alternatives, see dmoz.org/Computers/Software/Backup. Centered's Second Copy (www.centered.com) is worth a look.

If you don't have GoBack, you can still record a "disk image": an exact copy of the hard drive. This will at least take you back to the point where you took the snapshot. The best known examples of software which can do this are Symantec's Norton Ghost (www.norton-ghost.com), PowerQuest's Drive Image, NovaStor's IntantRecovery, and IYS' EZ-Imager. However, most of them are aimed at professional users, and so may require more computing expertise than most new PC users possess.

Either way, remember it is more important to back up your data - mail, addresses, project work, the draft of your blockbuster - than to back up the operating system or applications.

Those bits of software can always be restored from original discs which are, naturally, safe in a yellow plastic briefcase underneath your desk.