IT IS a sad fact that if you're using a Windows-based machine, you really have to take steps to at least provide a minimum amount of protection from viruses and spyware on your computer.

Nevertheless, it is still shocking how many users we've encountered who still use their machines without even installing at least an antivirus program, even though there are quite a few good ones that are free to install and use.

The fact is that if you use e-mail, an instant messenger or even web browser (in descending order of severity) you're very likely to get some kind of malware on your machine.

Even I was rudely reminded of this recently when I received a file from a friend via MSN Live Messenger which was a virus - as it turned out, my friend had not even sent it and the offending file was being automatically sent by an MSN trojan which infects Live Messenger and sends itself out to all the contacts on the chat client.

The same goes for e-mail clients - these days there are loads of viruses which spread by e-mailing themselves to all the contacts on a user's Microsoft Outlook list, which is all the more dangerous, as it appears like a legitimate e-mail from one of your friends.

Now that you perhaps understand the extent of the problem you're facing when using a Windows machine, here are a few free applications online that you can use not only to protect yourself from viruses and spyware, but also to clean up some of that junk on your computer and reclaim some disc space while you're at it.

Part 1: Security, security, security

THERE was a time when Norton Antivirus ruled the roost for antivirus applications, but these days it has largely turned into expensive bloatware, IMHO - I don't mind paying for an antivirus program, but Norton Antivirus is just too expensive by current standards and it slows my machine down more than I would like.

Luckily there are a number of free, yes free, antivirus applications out there. In fact, some of the best applications on the market are actually provided free.

AVG

I have been using AVG for some time now and successfully caught quite a few viruses resident on USB Flash drives and even e-mail.

AVG has a relatively clunky interface that I don't particularly like, but it is functional and it does work.

Best of all, AVG can schedule scans (though in the free version you only get limited control) and by default automatically updates itself once a day, ensuring that you always have the latest antivirus definitions installed on your computer.

AVG's success can be seen by the more than a million people who have already downloaded it at www.download.com, making it the number one download at the website.

Although AVG can be found at its official website (www.grisoft.com), it's actually easier to get it from download.com, as Grisoft makes the free edition intentionally hard to find on the official site.

Avast! 4

This application is a relative newcomer in the free antivirus space and provides a funkier interface (though not necessarily better) than AVG.

Avast!'s interface looks for all the world like a popular multimedia player, including having Play, Stop and Eject buttons.

It offers a whole host of interesting features, including a boot-time antivirus scan, the ability to scan instant messengers, Newsgroup and Usenet traffic, and even monitor your peer-to-peer downloads.

Overall, Avast! seems like a good competitor to AVG and although we haven't had much time with the program, it should seriously be worth considering, especially for power users.

Avast! 4 Home Edition can be found at www.avast.com/eng/download-avast-home.html.

Nanoscan

The main selling point of Nanoscan is that it claims to be the world's fastest online antivirus and antispyware scanner.

It is not meant to be a replacement for your installed antivirus solution, but more a complement that you can occasionally use as a second opinion when you suspect your machine has been infected.

Nanoscan is available at www.nanoscan.com and is actually part of the company that makes the Panda antivirus program.

We tried Nanoscan on various machines and it did indeed complete a scan in under a minute for all of them - however, since we had no infections present on our machines, we can't vouch for how effective Nanoscan is.

ThreatFire 3

ThreatFire 3 is a pretty unusual application in a number of ways. For one thing, the program can easily work together with your current antivirus program, firewall application or antispyware scanner without any conflicts.

More interestingly, however, is that unlike most antivirus programs that rely mostly on a "virus signature" database to detect known viruses, ThreatFire works by detecting the behaviour of malicious software, and therefore can theoretically block threats that are too new for other signature-based antivirus applications to handle.

Having said that, ThreatFire does have a signature database so it can automatically quarantine and block known threats.

Once installed, there is nothing to configure - ThreatFire sits in your system tray and will instantly quarantine any files that match its signature database or alert you if it detects a keylogging attempt, trojan behaviour or other virus activity and then ask you whether you want to quarantine the offending file.

You can get ThreatFire 3 for free at www.threatfire.com.

Part 2: Smert Shpionam

IN CASE you're wondering what the sub-heading is all about, it means "Death to Spies!" in Russian - otherwise known as Smersh, a real-world Soviet counterintelligence arm often mentioned in Ian Fleming's James Bond novels.

Post-Cold War, we suggest that Smersh be a term to refer to antispyware programs or the act of eliminating spyware and malware from your PCs.

The main problem with antispyware applications out there is that there is currently no central body that collects information and disseminates it to other antispyware companies like there is for antivirus companies.

As such, there is usually no one antispyware application that will capture all the spyware and malware that your machine could get infected with.

Therefore, we always recommend that you have at least two or three antispyware applications installed on your PC - with Windows Defender (which is a bundled application on Windows Vista and freely downloadable at Windows Update for XP users) one of them.

Unlike other free antispyware scanners which only scan and remove spyware from your system, Windows Defender actively protects you from getting some of that spyware and malware in the first place.

Ad-Aware 2007

Possibly the first or at least one of the earliest antispyware applications out there, Ad-Aware has been constantly updated over the years and yet still has a free version available to users.

In its current incarnation, Ad-Aware is a powerful scanner and has been proven to capture a large number of spyware and malware on PCs.

You can get Ad-Aware 2007 from www.lavasoftusa.com.

Spybot Search & Destroy

Spybot Search & Destroy is the other popular antispyware scanner.

Not many people know this, but Spybot has a TeaTimer component, which actively blocks and alerts you of any changes to your system and registry settings.

The only downside to TeaTimer is that it is sometimes a hassle because it will pop up an alert and ask you to confirm any changes - even when you're installing legitimate software like games and other applications.

Like Ad-Aware, Spybot is an essential item in the constant battle to keep spyware and malware from taking over your system.

You can get it at www.safer-networking.org.

Part 3: Clean that computer

IF YOU are looking to regain some space on your PC, an application we recently discovered is CCleaner, a freeware application that cleans out temporary files and unused files from your Windows system (both Vista and XP are supported).

Upon installation, CCleaner is configured to scan and then remove temporary files from a number of applications, including Internet Explorer, Firefox, Opera and a whole host of other temporary files that gather as you use your PC.

More interestingly CCleaner can clean the backup files and Hotfix uninstallers that accumulate when you visit Windows update.

Deleting Hotfix uninstallers of course mean that you can't uninstall them later on, but most of the time, fixes in Windows are never uninstalled anyway.

Deleting these uninstallers could actually get you back gigabytes, yes GIGABYTES of space on your computer, depending on how long you've been using your machine.

CCleaner also has a registry scanner and cleaner, which is quite highly regarded although we haven't tried it ourselves, after having universally bad experiences with other Windows Registry cleaners.

CCleaner is available from www.ccleaner.com. The application itself is small and can check for updates every time you start it up.