Kariudo wrote:For anti-spyware... Spybot Search and Destroy, Malwarebytes, Ad-Aware are the big (free) ones.
I'd not bother with Ad-Aware, personally...I used it for years alongside Spybot, and eventually it got to the point that Ad-Aware couldn't find anything that Spybot couldn't also. And considering Ad-Aware does run in the background at all times and when you launch the GUI interface it eats up resources like nobody's business, I just ditched it and went with Spybot only. A few years ago it was different - the two of them together could find and handle different problems (and Ad-Aware was actually the first anti-adware program I ever used, didn't find Spybot until later), but the need for it has kind of shrunk drastically, at least for me.
ZoneAlarm Free (firewall) - the more in-depth advice on that was already given
SpyBot S&D (anti-spyware, perhaps some general anti-malware capabilities - I seem to remember it detecting Trojans before) - remember to update definitions and Immunize!
Firefox (currently 3.6, but whatever the current version happens to be at the time), with AdBlock Plus extension. Do not use IE.
CCleaner (for later Temp, Registry, and Startup maintenance)
Defraggler (for optional defragging)
...and keep Windows itself updated with the relevant Service Packs and updates from Windows Update/Microsoft Update. If you don't want to worry about doing this, set Windows to use Automatic Updates (which I believe is the default anyway; just let it do its job).
After all that, then it's entirely up to you to pick an antivirus. You'll find suggestions for Avast!, AVG, Kaspersky, or so on. Or you could use HijackThis and get more specific instructions for your problems. I don't use an antivirus, haven't in years - but I know what I have to do to avoid them, and remove them manually if I have to (although I used the free version of Avast! to help with troubleshooting my sisters' computer back in October). Avast! seems pretty solid, at least to me.
A wholly-different route, but less error-prone, is to install Linux. Since Linux, like Mac OS X, is pretty much immune to this crap, you don't have to worry about junk getting in. Unlike the Mac, Linux can be installed on a regular PC and is typically completely free of charge (typically, because there are some business oriented distributions that are actually sold, but this price tag is mainly for the tech support and/or certain pieces of patent licensing if you get a distro loaded down with DVD software and so on - this latter point only applies is you get such software packaged with
the distro, however). The downside, like the Mac, is that the software selection is different than on Windows. You can use Wine to run Windows programs, but how well they work is up in the air (Wine is also available for the Mac, either in a vanilla form, which I've honestly never gotten to work right on Tiger, or as Crossover; the Linux version is the original, though). But if all you need the computer for is internet, email, word processing, and watching videos/listening to music, then these software availability issues aren't something you need to worry about.
Email (Evolution - or Thunderbird, but you have to install it separately)
Word Processing, spreadsheets, and other 'office' stuff (OpenOffice.org)
Watching videos (SMPlayer or VLC)
Listening to music (Rhythmbox, Banshee, Amarok, Audacious, Songbird...there's tons of these apps, most of which bear a passing resemblance to iTunes - except Audacious; it looks/acts like Winamp).