How to prevent Malware:

1. Make sure you have an Antivirus, Firewall and Antispyware scanner installed.

If not present, here are some I recommend:
Never install more than one Antivirus and Firewall! Rather than giving you extra protection, it will decrease the reliability of it seriously! The reason for this is that if both products have their automatic (Real-Time) protection switched on, your system may lock up due to both software products attempting to access the same file at the same time. Also because more than one Antivirus and Firewall installed are not compatible with eachother, it can cause system performance problems and a serious system slowdown.

I also suggest to perform an online virusscan once in a while. Because what one virusscanner can't find another one maybe can. You'll find some good Online scanners Here.

2. Make sure your Windows is ALWAYS up to date!

An unpatched Windows is vulnerable and even with the "best" Antivirus and Firewall installed, malware will find its way through.
So visit to download and install the latest updates.

Effective July 11/October 11, 2006, Windows 98, Windows 98 Second Edition, Windows Me, Windows XP SP1 and SP1a will transition to a non-supported status. Read here for more info:
So make sure you update!

Also read the Top 10 reasons to install Windows XP Service Pack 2 (SP2).

Also, not only your Windows should be up to date, but also the programs you are using. This since many programs may contain Security leaks. To find out if your programs are up to date, run the Secunia Software Inspector.

3. Stay away from illegal/questionable sites.

This is one of the main causes why a computer gets infected. Visiting cracksites/warezsites - and other questionable/illegal sites is ALWAYS a risk. Even a single click on the site can be responsible for installing a huge amount of malware. Don't think: "I have a good Antivirus and Firewall installed, they will protect me" - because that's not true... and even before you know it, your Antivirus and Firewall may already be disabled because malware already found its way on your system.

4. Be careful with mail attachements!

Malware spreads via email as well, especially email attachements.
The most common ones are emails telling you that your computer is infected where you'll find the removal tool in the attachement, emails telling you that your password has changed which you'll find in the attachement, mails with productcodes in the attachement from software you purchased (while you didn't), attachements with so called Security updates etc etc...
Don't trust these mails, don't even open them but remove them immediately instead!

It may also happen you receive a mail from someone you know, but with a questionable attachement present and strange contents in the mail. In this case, this person - or someone else who has your address in his/her addressbook - is infected with malware (worm/spambot) and sends these mails without being aware of it.

Don't click links in emails from someone you don't know, because these links can redirect you to sites where malware gets downloaded and installed.

Mailwasher is a free and great Anti-spam tool which gives you the option to view your mails on the server, sort them and delete the spam mails and other suspicious mails directly from the server without them downloading to your mailbox.
For people who get dozens of spams daily, read this great article where it explains spam and how to deal with it: I hate Spam

5. When surfing...
  • Don't click on links inside popups.
  • Don't click on links in spam messages claiming to offer anti-spyware software; because most of these so called removers ARE spyware.
  • Download free software only from sites you know and trust. Because a lot of free software can bundle other software, including spyware.
  • Be careful when watching online videos, especially when they ask you to install a certain codec to watch the video. By default, your mediaplayer should already have the necessary codecs installed to watch online videos. In case you're prompted to install an additional codec while trying to watch a movie online, it may be a false alert and this so called codec may install malware. More info here and here.
  • Don't install plugins (ActiveX) if you're not certain what it is or why you need it.
A great program is SpywareBlaster. SpywareBlaster doesn`t scan and clean for malware, but prevents it from being installed in the first place. It blocks the popular spyware ActiveX controls, and also prevents the installation of any of them via a webpage.
How to use SpywareBlaster

The MVP Hosts File is a great addition to block bad sites. This is accomplished by blocking these sites through the hosts file.

Install Internet Explorer 7 or another alternative browser like Firefox or Opera for more secure surfing. (However, keep in mind, as long as you don't stay away from illegal/questionable sites, no browser will be secure enough)

Glubble is a great Firefox add-on if you're having kids and want to manage the sites your kids are allowed to see + extra additions.

6. Watch what you download!

If you want to install certain software, always go to the developer's site to download the software from. Then you can be sure you're downloading and installing the right software.
Beware of the fact that certain software (especially freeware) may contain/bundled with extra software including spyware/adware. So only install it when you're sure they are OK.
Read here for more tips about safe downloading.

To find out if what you download is ok and get more information about the intentions of software and other bundled components such as spyware/adware which may be present, use EULAlyzer. EULAlyzer scans the End user license agreements (EULAs) most software should show during install and provides a detailed listing of potentially interesting words and phrases, discovers if the software you're about to install displays pop-up ads, transmits personally identifiable information, uses unique identifiers to track you, or much much more.

The use of P2P Programs like Kazaa (which is bundled with adware/spyware btw), Limewire, Torrentsites, Emule, Bearshare... is always a risk, because you can never be sure what you exactly download. It isn't always what it looks like. Important to know is that many P2P Programs are also bundled with unwanted software (spyware/adware). To find out which ones are safe to use and which ones are infected, take a look here.
Also read this article about the risks of using P2P Programs.

7. More info....

... and tips how to protect your Pc, Protect yourself and Protect your Family:

miekiemoes - Microsoft MVP - Consumer Security