Anyone running a computer that's connected to the Internet should be well aware by now of the growing number of threats to security and privacy that pollute the online world. It's still not safe to browse the Web without taking preventative measures to protect a PC or network, but luckily there are plenty of options available that offer peace of mind.

If you don't have a firewall, virus checker or other forms of protection installed on your computer, it's way past time you got some. A more likely scenario is that you're not happy with the security software you have installed, for various reasons, and are looking around for an alternative.

Choosing from the wide range of dedicated and suite-based solutions is no easy task: many vary quite drastically in both their levels of protection and in how they affect the day to day running of your PC. There are quite a few things to consider when shopping around for such products, something we'll be looking at in this guide.

To begin with we'll offer a brief overview of the main threats and annoyances you're likely to encounter:

Viruses: everyone's heard of computer viruses, but what once used to be a genuine daily concern is now far less of a problem thanks to advances in readily available security. There are many types of virus, most of which typically spread through your system by being inadvertently 'run' by executing a file or program from an unknown vendor or e-mail address. Their effects vary from totally disabling your machine to simply proving a nuisance, but regardless they're something you want to avoid.

Hackers: rather than a file or program created with malicious intent, hackers are individuals who exploit security holes in a network to gain access to a computer. Their intentions can vary from simple vandalism to theft of passwords, important files or financial data. Since hackers adapt with security measures they are harder to comprehensively block than most other threats, but a decent firewall will put most of them off even trying.

Spyware and adware: these sorts of threats are usually designed to invade your computer's security and gather information for various purposes. At its worst, spyware can collect personal information such as passwords or financial details stored on your PC and forward them to a third party. Adware tends to be less dangerous and usually involves automatically playing or displaying advertising material on your computer without your consent, often gathering information from sites you've previously visited to focus subject matter towards your interests.

Spam: spam is more of a nuisance than a threat; otherwise defined as unsolicited mail advertising products or services being sent to your e-mail account without your permission. Spam wastes people's time and eats up network bandwidth but is rarely 'dangerous' in the sense of the more potent threats outlined above.

All of these security concerns need to be protected against and the method you choose depends on your requirements. There are two real routes you can go down here: either you choose to pick up specific software for each - for example a virus-checker, anti-spam utility, anti-spyware tool, etc. - or you pick up a suite of tools that covers everything in one package and often much more.

Suites are proving to be popular solutions both for convenience and piece of mind, but on the down-side they're more expensive and often quite demanding on system resources. Norton 360 from Symantec, old-hands at system security solutions, is a new suite of tools that manages to protect you against just about every type of threat without hogging system resources too much. It's also a pretty good 'install and forget' solution, and will happily monitor your computer and correct problems without bugging you for advice. The downside of this is that it doesn't offer the same degree of control as alternative tools like McAfee Total Protection 2007, Steganos or the latest versions of Zonealarm and Symantec's more professional suite, Norton Internet Security.

An alternative to picking up a suite of tools is to buy the specific protection you need individually. It's unlikely you'd want to pick up four or five applications to make sure you cover everything, but you'll find that a lot of common software contains built-in protection against various threats and annoyances. The popular web browser Mozilla contains a pop-up blocker, for example, while many e-mail services will filter junk mail for you, and Windows itself comes with a built-in firewall. Picking up a suite of security tools may therefore end up duplicating a lot of the protection you're already getting and you might not consider it worthwhile.

Just about all suites of security software include a firewall, and considering software firewalls tend to be the most demanding of security tools, both in terms of requesting user intervention and on system resources, installing one is something you may want to avoid. Of course you do need a firewall of some type, and can use the Windows Firewall if you so wish, although most people 'in the know' will argue that in comparison with competing independent software firewalls, Microsoft's doesn't tend to fare too well. Another very popular alternative to a software firewall is a hardware firewall.

We're mostly concentrating on software in this guide, but dedicated hardware firewalls are an option. However, they are now far more commonly found in broadband routers like Zyxel's NBG-415N and Billion's BiPAC 7404VGO. Typically you'd want a hardware firewall to safeguard a network, since any machines that are connected to the Internet through this router will automatically be protected.

In contrast you'd need to install a software firewall on each machine to secure the network the hard way. However, you don't need a network to use a hardware firewall, and many users are opting for this as a relatively low-maintenance solution. There are differences in operation, however: where a hardware firewall can block any potentially malicious access from outside a network, few are able to manage or prevent software installed on your PC sending data out.

Hardware firewalls are pre-configured with a set of factory security settings and tend to work just fine without intervention using these rules, but if you want to tweak or adjust your hardware firewall this can be an awkward process. In comparison it's relatively straightforward to control and customise a software firewall to behave in a specific way towards each of the applications on your system. Generally speaking you don't need a software firewall if you have a hardware firewall, and since hardware firewalls don't tend to affect system performance they are gaining in popularity among home users.

Turning now to anti-virus software, if you choose not to opt for a suite of tools then a decent anti-virus package is an essential purchase, most notably because unlike firewalls, Windows doesn't supply you with one by default. If you're running a hardware firewall you'll find that a decent anti-virus package along with some anti-spyware tools (if they're not included) is often a far more resource friendly way to protect your PC. Best of all you can pick up some pretty impressive anti-virus tools for free, such as the free edition of Grisoft's AVG. Dedicated anti-virus tools are becoming less commonplace, with many manufacturers preferring to bundle this protection with other security tools, such as G Data. Choosing a specific anti-virus package is quite tricky, since the performance and level of protection tends to vary with each new release. Thanks to the ability to regularly update virus definitions quickly and easily across a broadband connection you'll find most modern packages offer a decent level of protection.

Anti-spyware software is going the same way as dedicated anti-virus applications, with combined packages becoming far more common. PC Tools' Spyware Doctor 5 is impressive for dedicated spyware prevention, and is also available with added anti-virus tools. Most of the time you don't need to pay for software to protect you against spyware, since a range of excellent free tools such as Ad-aware and Spyware Blaster will work just fine on home PCs.

In conclusion it's still extremely important to protect your computer against outside threats, but with a wealth of options available it's not difficult to shore things up pretty quickly. The biggest decision will revolve around whether to pick up a suite of tools for comprehensive all-in-one protection, or to opt for the more resource friendly but slightly more time-consuming option of using the Windows Firewall or a hardware firewall and picking up anti-virus and anti-spyware separately, which as we've discussed is often available for free.

Which to choose is often based on your degree of experience with PCs, the size of a network or sensitivity of potential files or other content on your machine and other priorities individual to the user. Always look out for reviews of the very latest suites and individual tools from big names such as Symantec, McAfee and ZoneAlarm, along with successful additions to the market such as BitDefender, Kaspersky, PC-cillin and AVG to see how successful these updates are in an ever changing industry.