You're a little curious about this new Windows 8.1, but you're also a bit scared at the same time, since you've heard that it's such a big adjustment from good old Windows 7.
Fear not, though, there's a way you can test the waters while still holding onto your tried and true system software — by setting up a dual-boot system. Installing Windows 8.1 this way gives you a clear, clean choice screen at system start-up allowing you to select which operating system version you want to use.
So how do you accomplish this? It's really not much more difficult than your typical Windows installation, with a couple of preparatory steps before you start the actual setup.
Follow the procedure below and you'll be able to switch back and forth between operating systems at will.
There's one preliminary note you should be aware of, though: This multi-boot setup only works with Windows 7 and Vista. To set up a multi-boot system with Windows XP or Ubuntu, you'll need to download a third-party multi-boot tool such as the excellent EasyBCD from NeoSmart Technologies.
Step 1: Back up!
Before you attempt this procedure, you should back up your existing Windows PC. You never know what will happen when installing a new OS. At the very least back up all your photos, videos, and documents. A complete image backup of your hard disk is preferable, however. Windows 7 has a built-in backup feature to secure your data files, but for image backup, you'll need third-party software such as ShadowProtect, for example.
Step 2: Partition
You'll have to create a partition of at least 16GB (20GB for 64-bit Windows 8.1) for your side-by-side Windows 8.1 and 7 installation. To do this, type "disk management" in the Start button's text box, which will display a "Create and format hard disk partitions" choice at the top of the Start panel. Click on that to open the Disk Management utility. You'll probably have two partitions. Right click on the largest one, and choose Shrink Volume from the context menu.
A "Querying Shrink Space" dialog box will appear for a while, and then another message will tell you how much free space can be squeezed out of the drive. Enter a size above 16GB for the 32-bit version of Windows 8.1 and over 20GB for the 64-bit flavour, and then hit the Shrink button. This will create an Unallocated section equal to the size you chose in the chart at the bottom of the window. Leave it be for now, we'll let the Windows 8.1 installer take over from here.
Step 3: Download the Installer
Now it's time to actually get your copy of Windows 8.1, in the form of a downloaded ISO disk image file. There are several ways to go about this, which I've explained in my guide to downloading Windows 8.1. You can download Windows 8.1 Preview from Microsoft's Download Windows 8.1 Preview page. You have a choice between 32-bit and 64-bit; since most modern PCs are 64-bit capable, that's a better choice. Use Windows 7's disc image burning capability to create an installer DVD from the ISO file (by clicking Burn Disc Image from its right click context menu), or you can create a bootable USB key using the Windows 7 USB/DVD Download tool. You must boot to the upgrade disk or USB drive: You can't create a dual boot system by starting the installer within Windows while it's running.
Step 4: Run the Windows 8.1 Installer
Pop in the installer DVD you burned or the USB stick you prepared, and restart your PC. Choose your language, then "Install Now." You'll need a product key that matches your installer ISO. For the Windows 8.1 Preview installer, for example, the key is NTTX3-RV7VB-T7X7F-WQYYY-9Y92F. Accept the software license, and after this, choose Custom, not Upgrade. Now you're presented with the choice of partitions, so click "Drive options (advanced)" and then select the Unallocated space we created in step 2. Next, click New from the drive options icons below. Accept the full size displayed, and hit Apply.
Now we've got a freshly formatted partition to install Windows 8 on. Hit Next, and setup is off and running. Go have a coffee or other snack of your choice; it takes about 20 minutes. Note that there was no choice for specifically creating a multi-boot setup — since you used a separate partition, that will be enabled automatically.
Step 5: Restart your new system
Your system will reboot into Windows 8.1, where you'll go through the typical first-run options of choosing a colour pattern, Wi-Fi connection, and Microsoft account. But the next time you reboot the PC, you'll see the option screen shown below.
By default, this screen displays for 30 seconds, and then Windows 8.1 launches. To change that default to your older OS, choose "Change defaults or other options" from the bottom of this multi-boot screen. Here you can change the timer value and the default boot operating system. You can also use troubleshooting tools like Refreshing or Resetting your PC, and you also have access to advanced options like system recovery and a command prompt.
Now it's time to play with your new OS, which has been significantly improved in the 8.1 version. For more on Microsoft's refresh of its desktop OS, check out our in-depth look at Windows 8.1.