PC Firewalls. You know you need one, but again there are so many that it’s hard to choose.
Much as with anti-virus, there are many good options, both paid and free, but I’ve never used a pay firewall and, for home computing, I don’t see why you should either.
I’ll start with my recommendation and then mention others I tried along the way. For Windows Vista and 7, etc., I recommend Comodo Free Firewall. It’s light on resources, has a pretty quick learning curve, and it hasn’t let anything through since I started using it.
The only downside to Comodo is that you have to installing it with care in order to avoid installing bloatware, and even so, it might install some crappy toolbar or some such. For that, I recommend going into “Add and Remove Programs” afterward, and removing whatever crapware managed to install.
For Windows XP I still use Zone Alarm, which runs light and used to be my favorite all-around firewall. Unfortunately, their new version for Vista/Windows 7 is bloated, sluggish, and hogs system resources.
I have tried Windows Firewall, which many people swear by, but I’ve found that it misses things that Comodo and Zone Alarm catch, and it’s not as easy to get a view of what exactly it’s doing in the background.
So it’s Comodo for me, for now, until something better and leaner comes along.
One last thing, as with Anti-Virus, you want to be sure to only be running one Firewall at a time or they can cancel each other out. So make sure to shut one off before trying another.
Next: Good free software and some places to find it.