Flickr/MFinChina

A worm called Downadup or Kido is reported have infected at least 3.5 million Windows PCs in the world, with more computers being infected at a rapid pace. This is the largest known group of zombie computers. Does this scare you? Better gear up to prevent infection from rouge viruses doing rounds on the Web, computer networks and removable media such as USB drives.

Keep your Windows updated

You can keep your Windows updated by turning on automatic updates through Control Panel.
If you want to stay updated without Windows taking charge, there are some good options available.

WindizUpdate: It is a Firefox plugin that allows one to download Windows updates. It's an intelligent program that will install only latest updates, weeding out obsolete ones.

AutoPatcher: It gives you the control on the updates to be downloaded and also save you from the hassle of downloading the same updates each time you reinstall Windows on your PC.

CTUpdate: CTUpdate is a collection of script that acquires the complete update library for selected operating system from Microsoft's servers and creates an ISO image for burning a disc. Insert this disc into a Windows system that you want to update and run updateinstaller.exe. It creates a temporary account, installs updates and reboots without user interaction, and then removes the account when it's done.

Windows Updates Downloader: WUD enables to download all of the current Windows updates that are contained in update lists, which allows you to choose updates depending on the version of Windows. Once WUD has complete it's downloads, you integrate them into your Windows source using one of the many popular tools for pre-installation Windows configuration and component removal at your choice. One such tool is nLite. It allows you to create customized Windows installation by removing unwanted components and adding your own.

Install security patches

Install security patches released by Microsoft. Remember to install the patch released to remove the worm hole (MS08-67) that Downadup capitalizes upon. The patch, which applies to all supported versions of Windows, is available from the Microsoft Update Website, or via Automatic Updates.

Deploy a guard

Install a good anti-virus and keep it updated. You can use free versions of Bit Defender or AVG Antivirus.

Safety on the Web

Use Mcafee Site Advisor, a plugin for Firefox and Internet Explorer browsers, to avoid clicking on harmful links in Google or Yahoo search results, and also to know if the site you are visiting can damage your computer.

Turn off autoplay

Turn off autoplay feature to avoid infection from discs, USB drives, memory cards, etc. Scan the media with an updated anti-virus before opening it.
To turn off Autorun in Windows XP, open My Computer, then right click on the icon for your CD/DVD player, and select properties. Click the "AutoPlay" tab. Then, for each file type, select "take no action" and hit "apply”. In Windows Vista, turning off AutoPlay is easier: Go to "Control Panel”, then "Hardware and Sound”, then "AutoPlay”, and then just remove the check mark in the box next to "Use AutoPlay for all media and devices".

Additional resources:
Security at home/Microsoft