Unless you've bought a new PC in the past two years, there's a good chance that you're still running Windows XP - plenty of users are. Microsoft would obviously like you to upgrade to Windows 7, however, and now could be a wise time to make the switch.

Unfortunately, while an upgrade over the existing Windows installation is relatively simple to do from within Vista, the software giant hasn't made it easy to upgrade to Windows 7 from XP. Never fear: we'll walk you through the process.

Microsoft's advice is to transfer your personal files and folders to an external storage device, install a clean version of Windows 7 on your PC's hard drive, then reinstall all your files and programs. You can do this manually or with the so-called Windows Easy Transfer program. But, even if you can get this to work, it'll merely help transfer your files to an external hard drive. You'll still need to manually reinstall all your programs, enter their serial codes and configure them.

There are alternatives to all this hard work. For example, there are utilities that promise to help synchronise data between PCs - in this case, between your machine with XP on board, and the same PC after Windows 7 has been installed. Alternatively, you could install Windows 7 and boot XP in a virtual environment. With both OSes running at the same time, you can easily return to your 'old' PC at any time and transfer files and settings at your leisure.

With all the work required to make the move to Windows 7, you may instead be considering buying a new computer. But plenty of readers have decided that this new PC need not necessarily be a Windows one: both the Linux and Mac platforms are growing in popularity.

Now that Apple has transitioned all its Mac hardware to use Intel processors, it's quite easy to run Windows on the Mac: either natively on a partition of the hard disk (known as Boot Camp); or virtualised, within Mac OS X itself.

Three apps make the latter option possible: VMware Fusion, VirtualBox and Parallels Desktop. We'll be demonstrating the process using Parallels Desktop in the following walkthrough.

Virtualise XP on a Mac

You will need: Parallels Desktop Switch to Mac Edition (£74 inc VAT)

Step 1. First check that both systems are sufficiently well-specified for first transferring and then running Windows on the Mac. You'll need an Intel Mac running OS X 10.4.11 or later, and a Windows PC with XP SP2 or later. Your Mac will need 2GB of RAM and disk space to match that used by your PC.

Parallels Step 1

Step 2. Install Parallels on the Mac. This process should take less than 5 mins. When finished, eject the disc and load it into the Windows PC you're preserving as a virtual machine (VM). Run the Parallels Transporter program setup within Windows, and look out for the 'Parallels Transporter Agent' shortcut created on the desktop.

Parallels Step 2

Step 3. Connect the supplied cable between the two PCs (preferably between two USB 2.0 ports). Windows will state that it needs to find drivers for the hardware to work correctly. Click through the wizard to install it. If it can't find the driver, you'll need to install it manually. If it worked first time, move on to step 5.

Parallels Step 3

Step 4. Next, right-click My Computer and select Manage, Device Manager. Look under the Network adaptors for the Parallels Ethernet Adaptor, marked with a yellow warning triangle. Right-click this, then select Update Driver. Next, direct the installer to C:\Program Files\Parallels\Parallels Transporter Agent\Drivers.

Parallels Step 4

Step 5. Open Parallels on your Mac and you'll be presented with a welcome splash screen. Select Migrate to start Parallels Transporter. Choose Physical computer and Parallels USB cable when prompted. Run the Parallels Transporter Agent on the Windows PC to transfer the contents of your hard drive to the Mac.

Parallels Step 5

Step 6. Once complete (it could take several hours), click through the agreement to reactivate Windows. Have your original serial code handy; if Windows was preinstalled on the PC, this information should be listed on a sticker on the side or base of the PC. Launch your VM by clicking the Start button.

Parallels Step 6