You can either update an existing installation of Windows 8 or install Windows 8.1 from scratch via ISO files from Microsoft.
Those of you eager to check out the new Windows 8.1 Preview have a few choices as to how and where to install it. Let's cut right to the chase and review the different options.
If you're already running Windows 8, you can simply update it to Windows 8.1 via the Windows Store, as CNET's Jason Cipriani explained earlier this week.
One word of warning before you proceed, however. The Windows 8.1 preview is essentially a beta of the new OS and is by no means a finished or polished version. Therefore, you shouldn't update to Windows 8.1 on your main or only PC. Instead, reserve the update for a spare or non-essential device outfitted with Windows 8.
Your first step in Windows 8 is to browse to Microsoft's Windows 8.1 preview page. Click on the Get it now button. At the Download Windows 8.1 Preview page, click on the Get the update button. You're prompted to open or save an msu file. You can open it directly or download it and then double-click on it to install it. You're then asked to install an update for Windows. Click Yes. After the installation completes, you're prompted to restart your PC.
Windows restarts to install the new update. Log back into Windows 8 at the lock screen. You should see a message inviting you to get Windows 8.1 Preview for free. Click on the link to Go to the Store where you can download the update.
If you don't have Windows 8 or don't want to update it, you can install Windows 8.1 afresh.
From any PC, browse to Microsoft's Windows 8.1 preview page. Scroll down the page until you see the section for ISO files. Click on the download link for the appropriate version, such as the English 64-bit version. Also make note of the product key. The ISO file is rather large, so it will take a while to download depending on your connection speed.
After the ISO file has completed its download, insert a recordable DVD into your CD/DVD drive. Windows 7 users can simply double-click on the file to open the Windows Disc Image Burner to burn the file onto the DVD. Windows XP and Vista users need to download a third-party image burner, such as Virtual Clone Drive.
After you've burned the ISO file onto the disc, you can now install Windows 8.1 on any PC from your new DVD. So, where can you install it without wiping out the OS on your main computer? Well, as I said before, you can hunt for a spare PC on which to install Windows 8.1 cleanly. If that's not an option, you have two other choices.
You can create a dual-boot scenario in which you preserve your current version of Windows and install Windows 8.1 to run side-by-side. CNET's Ed Rhee described how to create a dual-boot setup in a how-to article last year.
You can also run Windows 8.1 in a virtual machine within your current operating system. In one of my past articles, I explained how to set up a VM using free software such as VMWare Player and Oracle's VirtualBox.
Microsoft also offers an FAQ with further information on Windows 8.1.
Though still in preview mode, Windows 8.1 is certainly worth taking for a spin. And as described here, you have several options on how and where to spin it.