Antivirus
The very least that should be installed - here a few free packages ...
AGV Claims to catch 99.99% of viruses ...

AntiVir Made in Germany ... support is free of charge via Bulletin Board.

VCatch Automatically updates its virus definition list on your computer via the net.

F-Prot For DOS......er hello???  Used a lot as a 2nd (backup) AV program.  Free for private users.  Definitions updated regularly.

Firewalls
Most companies put in a firewall to prevent internet intruders/threats accessing their precious networks. Do the same for the pc at home. Do an online check at ...
Sygate Online Services

ZoneAlarm Not only stops stuff getting in but also stops programs from sending data out without you knowing. Highly recommended.

Kerio Personal Firewall If you're more 'technically oriented' and you enjoy messing around with firewall rules, ports, protocols, this one's for you. Look at bottom of page.

Sygate Even the most inexperienced web-surfer can enjoy the Internet with complete confidence and security.
support forum

Trojans
Short, fat , ugly things that climb out the mailbox at night...
ANTS One of the best freeware solutions available, has some very useful extra's.  Although a German program - English Ver is available here.

Trojans First Aid Kit (TFAK) - detects and removes the most commonly used Trojans around.

Patches
Keep the patches on your MS OS up-to-date.
Microsoft Hotfix Checker Scans all NT and/or 2K machines on a network from a single location and compares their currently installed patches with the latest ones available.

Microsoft AutoUpdate Does it all for you.

 

Ad-Aware
This program will tell you what spyware is sitting on your pc pumping info back to various sources - even if you only surf the web occasionally, use it.
Ad-Aware A free multi spyware removal utility, that scans your memory, registry and hard drives for known spyware components and lets you remove them safely.

Spybot A free utility that detects and removes spyware of different kinds from your computer, often used in conjunction with Ad-Aware.

Scripts
Scripts are mostly used for programming web sites. A script could be a virus or a Trojan but are normally harmless - here are some tools just in case.
Script Sentry Set it and forget it - it takes up exactly 0MB of memory unless it's needed.

Script Defender Intercepts requests to execute the most common scripting types used in virus attacks, can even be configured to intercept new script extensions as needed.

Web Bugs
Invisible graphic images on a web page that are designed to monitor who is reading the web pages.
Bugnosis There must be an sa influence here - Ag no sis???

SpyBlocker Blocks cookies, bugs, ads and spyware. It has a log so you can see what has been blocked. There's a trick for IE users utilising the ad-blocking - haven't got that going yet. Seems to be ok, but some cookies still get through.

Ad Blocking
Web adverts collect information like your IP address, operating system, links you've visited etc etc!
Proxomitron See Pop Ups.

SpyBlocker See Web Bugs.

WebWasher Removes most web advertising, tracking cookies, web bugs and pop-up windows. Additional features include auto-downloading of up-to-date url filters and the ability to filter harmful content-types.

 

Pop Ups
Miserable and HIGHLY annoying way of advertising or attention catching.
Proxomitron Have you ever opened a page, only for 10 others open simultaneously!!!  This program puts an end to that - what a pleasure.  Numerous other features which can be tweaked for smoother and faster surfing - highly recommended.

Ads Terminator Program download only. It does a v. simple task - edits the hosts file.

Supertrick How the hosts file can be used to stop pop-ups - how to manipulate it.  Look for the Supertrick link on the linked site.

Cookies
Yep - some are good and some make you fat ...
CookieWall Gives you the choice of accepting or permanently denying them.

Cookie Central Reams of info on the humble ...

Index dot dat Stores a list of web addresses visited by a PC's user and also contains old web-based e-mails. The file and all its logged data stay on your PC even after you have cleared your temporary internet files.  It cannot be deleted by regular methods - these two sites offer ways to delete the files.
What are those...
Solution for...
How to read what's in the files by The New Zealand Herald

Spider Will find all the index.dat files, display what's in them and gives an option to clean them out.