How to reinstall Windows

Before you begin
Because a clean install involves destroying everything stored on the Windows partition, you need a backup of the entire partition in case things go wrong. The best way of backing up is with a specialist imaging program such as Acronis True Image or Norton Ghost. Both of these permit the reinstatement of a backup even when the target hard disk contains no operating system.

The backup image is just for emergencies. You must also copy all the files you want to keep onto a removable hard disk or the hard disk of another computer on the same network (or CDs/DVDs if nothing else is available).

As well as documents, spreadsheets and pictures, don’t forget to copy contact details from your Windows Address Book or whatever you use in its place, and copies of your emails, Internet Explorer favourites and bookmarks from other web browsers. Make sure you have everything backed up and follow this Masterclass at your own risk.

Make sure you have paper copies of all the user names and passwords required by Windows, your broadband router, your Wifi network and any websites you visit. Next, download a free copy of Belarc Advisor.

When you install and run this program it displays a complete analysis of your PC in your web browser, covering all the installed hardware, software and Windows settings. The product keys of many programs are displayed and there’s a host of useful technical stuff. Print this list for reference.

Download the most recent versions of all the drivers required by the motherboard, printer, scanner, soundcard, network adapter and any other items of hardware. Store these on CD or a USB memory stick along with the Service Packs 1a, 2 and 3 for Windows XP, which you'll find on Microsoft’s support site, or Service Pack 1 for Vista.

If you have a broadband router, turn on its firewall to help protect the newly installed version of Windows until you have time to configure a full set of anti-virus, firewall and internet security tools. If you can arrange access to another internet-connected computer while you’re performing the clean inst all, you’ll be covered for just about anything that might arise.

Finally, ensure the computer is configured to boot from its CD drive. If not, you’ll need to modify the boot sequence within its Bios setup program.

The usual way of starting the setup program is to hit the Delete key shortly after booting, but for the correct technique refer to your PC’s manual or watch for onscreen messages after switching on. With the boot priority set to the CD drive, insert the Windows installation disc and restart the PC again.

Performing a Windows XP clean install
Boot the computer with the Windows XP CD in the drive. To confirm your desire to boot from the CD, press any key when prompted to do so. Wait while the setup files are copied from the disc and then press Enter to continue. Press F8 to agree to the licence terms and, if using an Upgrade version of XP, be prepared to insert a qualifying older version when directed.

The setup program recognises that there is an existing installation of Windows. At this point do not press Enter, instead press Esc to signal your desire for a clean install.

On the next screen select the partition containing the existing version of Windows XP and press D to delete it. You’ll be asked to press Enter to confirm your choice, and then to reconfirm it by pressing L.

The deleted partition is now labelled as Unpartitioned space. Select this and press C to create a new partition. Press Enter to use all the unpartitioned space for Windows (or reduce the suggested size if you want to leave space for additional partitions). Once the partition has been created, select it and press Enter.

The partition must now be formatted. Choose one of the suggested format types (Fat 32 or NTFS) and press Enter. Unless you have reasons to prefer Fat 32, then NTFS is the one to go for.

Choosing the Quick option saves a great deal of time but skips the important disk checking that is performed during a full format.

Once the partition has been formatted, the Setup program starts copying files to it. When the files have been copied, Windows automatically saves its current state and then reboots the computer so that installation can continue using a graphical interface.

Because the computer is configured to boot from its CD you should ignore the message ‘Press any key to boot from CD’ this time.

The computer will then boot from the hard disk and proceed with the installation of Windows. Towards the end of the process you’ll be asked to chip in with a few simple details about your preferred settings.