Right, all done. Installed everything. All the AV stuff, Firewall, Ad Aware, Spybot, Spyware Blaster, Anti Trojan Watch, the lot.
Now, there does appear to be a problem. Every now and then, the whole thing freezes for a few seconds, then my screen goes blank for another couple of seconds, then when it returns, some of the system tray icons are missing, but according to msconfig 'Services', the items are all still running.
Any ideas?
Apart from that, everything seems to be running OK.
Thanks for all the help from everyone so far -- you're not gettin' away yet!