There are two main ways to upgrade to a new version of Windows Operating system: an upgrade install and a clean install. When considering installing a new version of Windows on a computer, the first issue is whether your computer is fast enough for the new operating system. Microsoft and others publish both minimum and recommended horsepower (cpu speed, installed ram and available hard disk space) on their web sites.

The simplest way to get a completely working copy of Windows Vista is to buy a new PC. Wait, we’re serious: Even though PC makers tend to fill their machines with oodles of useless utilities, add-on programs, and other sludge, the one thing you can always be sure of when you buy a new PC is that Windows Vista is going to work out of the box. That is, all of the hardware that comes as part of your new PC purchase will work without any additional effort on your part. You won’t have to step through the various setup-related issues we discuss later in this article. In fact, if you did purchase a PC with Windows Vista preinstalled, most of this article won’t apply to you at all (well, except for the deployment discussion at the end of the article, assuming you got a Vista DVD with the new PC). You should be able to simply turn your new PC on and get to work. One thing that PC purchasers should know about is how to restore their system, or return it to the state in which it was in when new. Virtually all new PCs sold today include a means by which you can do this.

Most of the time, you can restore your PC using a special hidden partition on your hard drive. Other PC makers actually include what’s called a restore disk, or restore DVD, with the system. Check your documentation to be sure that you know how to restore your system if you need to. And when you’re removing all of that junk that the PC maker installed on your previously pristine Windows Vista installation, be sure you don’t remove anything you’ll need to recover your system.

If you purchased a copy of Windows Vista on DVD at a retailer or online store, you can install Vista using Microsoft’s new Interactive Setup application, which guides you through a series of steps while installing Vista. There are three primary ways to install Windows Vista using Interactive Setup: A clean install, where Windows Vista will be the only operating system on the PC; an upgrade, where you upgrade an existing operating system to Windows Vista, replacing the old with the new; and a dual-boot, where you instal Windows Vista alongside your old operating system and use a boot menu to choose between them each time you reboot. We’ll examine all three methods in this article.l

A clean install of the operating system is our preferred method for installing Windows Vista. Although it’s possible to upgrade to Windows Vista from certain previous Windows versions (see the next section), this path is perilous and can often result in a Frankenstein-like system where only some of your applications work properly. In our opinion, it’s best to start with a clean slate when moving to a new operating system, especially a major release like Windows Vista. Be sure to back up your critical data before performing a clean install. Typically, you will wipe out your PC’s entire hard drive during a clean install, so any documents, e-mail, and other data will be destroyed during the process. Also, make sure you have all the installation disks for the applications and hardware drivers you’ll need to reinstall after Vista is up and running.

There are two ways to make space for Windows Vista on your existing PC. You can either add a second hard drive, using the new hard drive exclusively for Windows Vista, or you can partition your existing hard drive, creating two logical hard drives, or partitions, one for Windows XP and one for Windows Vista. The former method is the preferable one because it doesn’t require you to deal with messy partitioning software and potentially endanger whatever data you already have on the C: drive.

On the other hand, you do have to go through the effort of installing the hard drive, which can be dicey if you don’t know your way around the innards of a PC. And of course, some desktop PCs and most notebook PCs can’t be upgraded to support an additional hard drive. In such cases, you’ll need to partition the only hard drive you’ve got. If you’re going to install a second physical hard drive, there’s not much to say: Follow the manufacturer’s instructions, and you should be all set. Modern hard drives are quite capacious and will present no problems during setup.

If you’re going to partition your existing hard drive, life isn’t so simple. Most partitioning tools, like the ones built into Windows, are what’s known as destructive partitioning tools—that is, they literally destroy whatever was on the disk while partitioning. What you’re looking for is a non-destructive partitioning tool, one that will let you slice an existing hard drive or partition into two or more partitions, while leaving all the data—and the operating system and applications—intact on the first. There are various commercial partitioning solutions out there. We use and recommend Norton PartitionMagic, which has always been reliable. But there are various free partitioning solutions out there as well. Just be careful: This is your data you’re messing with, and if the partitioning solution you use accidentally makes your hard drive inaccessible, don’t say we didn’t warn you.

Also, you need to be sure to defragment your hard drive before partitioning in order to save time later (partitioning tools will defrag for you as needed, but aren’t as efficient or fast as dedicated partitioning tools). Finally, make sure you create a partition with enough space on it to install Windows Vista. Microsoft specifies that Windows Vista requires 15 GB of free space for the premium versions of the operating system (Home Premium and Ultimate).

But remember you’re going to want to install applications and so forth. So the more space you can spare the better. To make it easier on yourself, preemptively name the new partition Vista or something similar, so you can more easily recognize it during Setup. You don’t want to accidentally wipe out your XP install.