Got all three computers hooked up with it. The two which had virus problems immediately stopped having virus problems. The other one revealed a spyware application which was monitoring my internet usage and reporting back to a corporation somewhere without my permission. Now it isn't. So, I'm pretty happy with ZoneAlarm.

The home computers can no longer communicate amongst themselves, however. I'm sure that's a temporary setback. Just need to figure out how to identify the other computers as being safe...

The virii are .VBS files which mysteriously appear in a half dozen directories. MacAffee VirusScan identifies them as intruders the moment they appear, and deletes them. I routinely scan the entire hard drive with all the time-consuming options checked. (This happens roughly once a week, since that's how often VirusScan gets updated) I also search the drives periodically for .VBS files, but since VirusScan started recognizing the problem (since the latest engine upgrade, basically), those just don't stick around very long.

I originally thought there was a trojan horse of some kind generating these .VBS files behind the scenes. But I've identified the specific virus, and know the methoods by which it spreads. More importantly, though: No virus has appeared on either of those machines since ZoneAlarm was installed.

I don't want to jinx it by announcing that they're cleared out, but I think the coast is clear. For now, anyway.

More importantly...
I still have a solid internet connection. Things have always been completely bogged down by early evening, and that's been the case for a LONG time. (I remember Justin giving me a hard time about it during the Frog Prince - he thought my troubles were a symptom of DSL not being as good as his cable modem) My guess is a lot of problems were strictly virus related.