Install two versions of Windows on your PC for compatibility or just familiarity with our comprehensive guide
he main reason for setting up a dual-boot system is to keep hold of a familiar operating system while experimenting with a new one. Each new version of Windows does things slightly differently with regards to their predecessor, and you may want a little time to run the two side-by-side as you familiarise yourself with a new way of doing things.
There are also questions of stability - both Windows XP and Vista were notoriously flaky prior to the release of Service Pack 1 - and compatibility too. Will your existing software and hardware work with this new version of Windows? If not, keeping hold of your old copy of Windows gives you breathing space while you hopefully wait for a compatible update or driver to be developed - or failing that, the time you need to save up to purchase a replacement that is compatible with the new version of Windows.
In an ideal world, you'd simply take your new copy of Windows and follow this guide to set it up alongside your existing copy of Windows. However, if you've purchased an upgrade copy of Windows Vista or Windows 7 you should read the box below before continuing.
Before you dual-boot
There is one major restriction, which may scupper your attempts at installing a dual-boot system. Microsoft has tightened the installation procedure to make it impossible to install an upgrade version of Vista alongside your existing copy of XP. Because your upgrade copy is a part-exchange, your existing copy is deactivated after you install the new version, and can no longer be used - Microsoft wonít let you use old and new together.
This restriction will almost certainly apply to both XP and Vista when WIndows 7 is released as well, but for the moment you can happily install the Release Candidate alongside either version of Windows without affecting your existing licence.
Prepare your hard disk
The first thing you need to do is sort out where your new operating system is going to go. It has to be installed to an internal hard drive - external USB and Firewire drives aren't quick enough, so if you don't have a second internal hard drive fitted you'll need to divide up your existing hard drive by partitioning it.
The act of partitioning divides up a single large hard drive into two or more smaller drives, each of which is treated as a separate hard drive by your PC. Because your hard drive will be divided up into smaller chunks, you'll need enough free space on it to not only create a suitably sized partition for the new version of Windows, but also to leave enough free space on the existing partition for Windows to function smoothly.
How much space you'll ultimately need to satisfy both conditions depends on the version of Windows you're currently running, and the version of Windows you intend to install on the new partition. First, determine what size partition you need to create for your new version of Windows. If you're installing Windows XP, you shouldn't need more than 10GB, which should leave you plenty of room for a large number of applications. Windows Vista requires around 30GB of free space, and Windows 7 around 25GB. Double or even treble this figure if you plan to install a number of space-hungry applications such as games.
You'll also need to leave enough free space for your existing copy of Windows to function in: the following guidelines should be considered the bare minimum, so try to leave more if you can afford to: 5GB for Windows XP, and 10GB for Windows Vista and Windows 7.
Add the two figures together to work out how much free space you'll need, then click the Start button and select Computer or My Computer. Right-click your Windows drive (drive C in most cases) and choose Properties, then check the available amount of free space. If you do have space to spare - anything from 15-40GB - then you can go ahead and partition your hard drive.
Separate data from Windows
Storing your data on a separate drive to Windows is a good idea as we've discussed elsewhere on this site. One way to free up space on your main hard drive might be to purchase an external drive to store your data on - as data is moved from your system drive to the new drive you'll free up space. Alternatively, if your hard drive is large enough, you could simply create a third partition to store your data on.
It's a good idea to set up up this third partition or drive prior to installing your new version of Windows. Start moving data files and settings across to the newly created data partition. Once done, you can install your new OS and point it towards them too, enabling both to share email, documents and more besides.
WARNING: Whatever option you choose, don't assume that separating your data from Windows means you can get by without backing it up.
Partitioning is traditionally a destructive process, so you'll need to install a third-party partitioning tool to partition your drive without data loss. The best free tool for the job is EASUS Partition Master, so click here to follow a guide to partitioning your hard drive.
Install your new version of Windows
If youíre adding a new version of Windows alongside an older version (such as Vista alongside XP), then the process from here is straightforward Ė just install the new version of Windows on to the newly created hard drive and itíll automatically set itself up alongside XP, with a boot manager appearing when you start up each time that enables you to switch between the two.
When installing your new OS, be very careful when choosing which drive to install it to Ė sometimes drives get mixed up, so donít assume the drive you want is necessarily in the same order as it appears in XP; instead, make sure the size and free space match the drive you created earlier. Consider adding a drive label to each partition prior to installing the new version of Windows to help you identify them: to do this, open Computer or My Computer, right-click the drive and choose Properties, then enter the label into the box on the General tab, which will help you identify it during the installation process.
Install an older version of Windows
In a perfect world, it's always best to install operating systems in order of age, eldest first. If this isnít possible Ė for example, you want to add Windows XP to a system already running Vista - then youíll need additional help.
If your system is running XP and youíre looking to add an older version of Windows, you might prefer to install 98 or Me as a virtual machine using a free program called VirtualBox (click here). To add XP to Vista or Windows 7 requires some jiggery pokery. Thankfully thereís a free tool called EasyBCD, which lifts it beyond XPís own boot manager. The walkthrough below reveals how it can fix the boot menu problem after youíve partitioned your drive and installed XP to the new partition.
Install Windows XP alongside Vista or Windows 7
1. BOOT FROM WINDOWS DISC
After installing XP you wonít be able to boot into Vista or Windows 7. To fix this, boot from your Vista or Windows 7 installation disc (click here to create a Vista rescue disc if you don't have an installation disc), opt to repair your PC and select Startup Repair. Vista will reset the boot file and youíll be able to boot into it again.
2. INSTALL BOOT MANAGER
You'll now be able to boot into your new version of Windows, but your XP installation will temporarily be inaccessible. To rectify this, click here and download EasyBCD. Once downloaded, double-click EasyBCD 1.7.2.exe and follow the instructions to install it.
3. LOCATE DRIVE CONTAINING WINDOWS XP
Click Start > Computer to locate the drive that Windows XP is installed on. Make a note of the drive letter that's been assigned to it - you may need this later.
4. ADD NEW ENTRY
Now open EasyBCD and click the Add/Remove Entries button. Under Add an Entry verify the Windows tab is selected, then select Windows NT/2k/XP/2k3 from the Type: drop-down menu. Type Windows XP into the Name box and click Add Entry (you'll see the drive letter has been greyed out).
5. VERIFY SETTINGS AND TEST
Click the View Settings button - you should see that the Windows XP has been allocated the correct drive letter as you noted in step three. If it hasn't, click Change Settings, select Windows XP from the drop-down menu and change the settings. Once verified, close the program and restart your PC. A boot menu should appear, so select Windows XP to verify you can boot into it. If you can't, boot back into Vista and tweak the boot menu settings in EasyBCD.