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PC Security

There are three main things that you need in order to keep your windows PC secure -
1 - Firewall
2 - Antivirus
3 - Antispyware

1 Firewall

A firewall is a bit like a gatekeeper. It monitors internet traffic coming into and going out of your PC. The reason for monitoring inbound traffic is to make it difficult for hackers to gain access to your computer and steal passwords or corrupt your files. Some firewalls also monitor outbound traffic. The reason for doing this is to prevent trojans that may have infiltrated your PC from sending passwords or other sensitive data back to the sender of the trojan.

Most of the internet security suites currently on the market include a firewall as part of the package. There are also several firewall only solutions available. One of the best known and popular firewalls is Zone Alarm. It's popularity is due mainly to the fact that it works well and there is a free edition in addition to the commercial edition. The commercial edition has more features as you would expect. The company that produces Zone Alarm also has a full security suite that includes antivurus and antispyware.

Even if you haven't installed a firewall you don't need to panic because Windows XP and Vista include a basic firewall which is usually activated by default when you install Windows. If the Windows firewall has been de-activated for any reason and you don't have any other firewalls then Windows will usually dispaly a warning in the system tray in the bottom right corner of the screen (assuming you have Windows XP service pack 2 or later).

One downside to firewalls is that they can sometimes prevent programs that need to access the internet from working properly. They can also prevent you from accessing a network connected printer on your home or office network. They can also prevent file sharing across a network. All of these problems can be resolved by configuring exceptions in the firewall configuration but this is not always easy to do. Ironically it is often the more expensive firewalls or security suites that seem to cause these problems.

Virtually all wireless (and wired) routers now include a firewall which is usually enabled by default. If you have a router with a firewall then you may not need a third party firewall running on your computer. In this situation the Windows firewall should be adequate.

2. Antivirus

The purpose of an antivirus is to protect your computer from infection by viruses. It does this by maintaining a list of virus signatures and comparing files on your computer with this list to detect virus infected files. It does this in three main ways.

The first is called "Resident Shield" in AVG or "active scanner" or "active monitor" on others. This works by scanning all programs just before they run to make sure they are not infected. Obviously this will slow down your computer by a greater or lesser amount depending on the individual antivirus. Some antivirus programs will slow your computer down much more than others. This slow down is very noticable on older computers with small amounts of RAM.

The second way is simply to scan all the files on your computer one by one. This might take anywhere from fifteen minutes to several hours depending on the amount of data on your computer and the speed of the computer. If you don't schedule a regular scan with the antivirus or run a scan manually by opening the antivirus control panel and selecting the option to scan the computer, then this just won't happen. This is one of the reasons why computers get infected even though they have an antivirus.

The third main way an antivirus protects your computer is by scanning all incomming emails for infections. Viruses usually spread by malicious web sites or email. Many viruses will scan your address book and immediately send a copy of themselves to everyone on your address book without your knowledge. This is why all emails need to be scanned even if they appear to be from friends.

There are probably more than 100,000 different viruses in existence and new viruses are being created every day which is why it is important to keep your list of virus signatures up to date. A virus signature can be thought of as the digital equivalent of a fingerprint used to identify individual humans.

Most antivirus programs will update their signature list on a daily basis. This updating process is often accompanied by a pop up window to let you know it is occurring. This daily update process should not be confused with scanning the whole computer for viruses. Many people think that because their antivirus program is updating every day that it is scanning the whole computer for viruses every day. This is not the case. In addition to regular updates you also need to do regular scans of the computer.

If the computer is at high risk of infection (e.g. the kids play on it) then scanning every day is probably a good idea. If the computer is only used to access safe well known web sites then scanning the computer once or twice a week will probably be adequate.

There are dozens of different antivirus programs on the market. Some are very good. Some are not so good. There are even some that are only pretending to be an antivirus when in reality they are actually spyware. These pretend antivirus programs will often "invite" themselves onto your computer and then pretend to run a scan which detects an alarming number of viruses. You will then be asked to buy the full version of the program for about $40 USD so that the detected viruses can be removed. Click the following link for an example of this


You also need to be wary of apparently independant web sites that claim to have tested all the top antivirus products and found "DoublePlusGood Antivirus" is the best in the world and a bargain at only $39.95. You often find that this independant web site is in fact owned by the same people that created DoublePlusGood Antivirus ...

Virus Bulletin is one independant organisation that specialises in testing antivirus products. They conduct in depth tests of most of the top antivirus programs and publish the results on their web site -
Virus Bulletin
The anitvirus programs that pass the test are awared the VB100 award. Please note that you will have to register (for free) to access the latest VB100 results.

Another organisation that conducts independant antivirus testing is -
AV Comparatives

You should never install more than one antivirus product on your computer because they will interfere with each other and slow your computer down. If you want to change your antivirus you should un-install the old one before installing the new one.

If you are on a tight budget you may prefer to get a free antivirus. There are several that are available. AVG and Avira are two of the better ones. Both of these products have commercial versions which include extra features but the free versions provide good basic protection. Please use the two web sites listed above to check out any free antivirus you may be considering downloading to make sure it really is an antivirus and not spyware in disguise.

3 Antispyware

An antispyware program protects your computer from spyware or malware. It works in much the same way as antivuirus programs by scanning your computer for known spyware signatures.

Spyware refers to any software that tries to obtain information about your web browsing habits without your consent or tries to get you to buy products online by hijacking your web searches for example. Spyware is commercially motivated. They are trying to make money. It often installs itself on your computer without your  permission and is nearly always harmfull to the operation of your computer.

Most of the newer internet security suites include an antispyware component as standard. It is also possible to get programs that just protect your computer from spyware.

Windows Vista includes an antispyware program called Windows Defender that appears to work quite well. You can also download this program for free for Windows XP by going to the Downloads section of the Microsoft web site. It runs unobtrusively in the background and does a quick scan for spyware once a day. You can also run a full scan of your computer if you suspect you may have spyware. To run a full scan, do the following -

- Click on Start and then move the mouse to "All Programs"
- Locate "Windows Defender" and left click it. This will open the Windows Defender screen.
- Left click on the small white triange just to the right of the scan menu at the top of the window.
- Left click on "Full Scan". This will do a full scan instead of a quick scan.

The full scan in Windows Defender is more thorough and takes much longer than the quick scan which usually runs every day.

In addition to the many commercial antispyware programs on the market there are several very good free antispyware programs. One of the better ones is "Spybot, Search & Destroy". This takes quite a while to scan the whole computer for spyware but seems to be quite thorough. There are several dubious antispyware programs with simillar names to Spybot so make sure you are getting the real thing.
Spybot Search & Destroy

Another good free antispyware is Ad-Aware from Lavasoft.

No antispyware or antivirus program will detect all viruses or spyware, so if one program does not fix your problem then it is often worth trying a different one. Having more than one antispyware program installed is usually not a problem but you should not have more than one antivirus program installed. You should un-install one antivirus program before installing a different one.