NOTE: This article is outdated. All programs listed here are old versions, and at the very least, should be updated. This article is kept for archival purposes. It will be rewritten, linking to the updated versions of these programs, as well as many more that are also now recommended.
Software No Windows User Should Be Without
Being as common as it is, Windows has lots of utility software written for it. Some of it is good, some of it isn't so good. This is a compilation of the better software that I've found, and where it can be found online. As a bonus, most of this software is free for home users.
A fair amount of free (free as in money) software comes with something frequently called adware, spyware, trackware, or various other names. This is frequently grouped together under the name malware.
This is software which can be as simple as a small program to download banner advertisements and show them in a free program's interface or pop-up windows. It can also be malicious enough to track your movements online, read files on your computer, intercept usernames, passwords and email addresses, and send all this information back to the author of the software, for purposes of target-specific advertising, spam mailing, or worse.
As an example, KaZaA Media Desktop (a free download) includes a program called CyDoor, which displays advertisements in the program's window. The CyDoor program, however, also has the ability to download program code from the internet, and run it on the local computer, without any input from the user. This could be a CyDoor update, it could be another piece of malware, or it could be an outright virus. There is no way to know what this software could do to your computer.
Free software isn't the only thing affected by this, however. Microsoft Windows itself comes with an extension to Internet Explorer which can send any search terms typed into an internet search engine back to Microsoft.
When Windows is installed, it also sets up a unique serial number for Windows Media Player, which allows any server on the internet to uniquely identify your computer. There used to be an option to disable this serial number in the preferences dialog for Media Player. The option has been removed in recent versions, but the serial number hasn't. This number could be used to track your movements around various multimedia sites. If one of them happens to require you to log in, you can potentially be personally identified on every multimedia site you visit.
Lavasoft Ad-Aware will scan your computer for any recognized malware, and remove it if you request. Some software will not work without the malware functional, however, so be prepared for this. KaZaA Media Desktop, for example, will not work without the CyDoor software available. There are workarounds for most of these situations, but they sometimes take a little bit of work.
With over 60,000 known viruses for Windows, anti-virus software in not only a good idea, it's an absolute necessity. You may think you're safe as long as you don't open attachments sent to you by email. While this used to be the case, it's no longer true. The recent Blaster worm which affects Windows NT, 2000, XP and Server 2003 infected a machine through a network service which cannot be turned off. If your computer is connected to the internet, it's at risk of being infected, unless the security patch supplied by Microsoft has been installed. There are also viruses which can install themselves through security holes in Internet Explorer simply by visiting a website.
AVG Anti-Virus Free Edition is, as the name implies, free, but only for home users. It includes free updates for the life of the product, and many features included in other expensive anti-virus software. Updates and scans can be scheduled, and it displays a log of any viruses found and actions taken by the program.
Registration is required to download the program, and a personal serial number will be sent to the email address you use for registration. This is required for installation of the program.
You may be concerned about receiving spam or advertising emails from this company, but I an assure you, I registered the program for myself nearly two years ago, and I haven't received a thing from them, other than the serial number when I first registered.
All in all, a very good anti-virus package, from a reputable company, and free to boot. What more could you want?
The disk defragmenter that comes with Windows does a fairly good job, as far as it is able. Because of the way Windows does file locking, however, it isn't possible for this program to defragment files that are in use by the operating system. This means heavily used system files, such as the Windows registry, virtual memory paging file, and others, cannot be defragmented while Windows is running. Since these files are used by virtually every program you may run on your computer, fragmentation within them can lead to significant slowdown for your system, which is impossible to correct with standard Windows utilities.
SysInternals PageDefrag will check the fragmentation level of your system files, and can then schedule a defragmentation of these files when you next boot your computer, before the files are locked by Windows. It's best to schedule a defrag at every boot, to keep your system files in the best shape possible.