BIOS is "Basic Input/Output System":
http://dictionary.reference.com/browse/BIOS
If on broadband (heck, even if you're on dial-up), you should also use a firewall. It's just a piece of software that helps prevent people from getting into your PC, and it also alerts/asks you if any program tries to access the internet. Some programs are OK (browsers, Windows update, etc), but if some rogue program tries to go online, the firewall can block access to it. However, a firewall is only as good as it is setup/used. If you just say it's ok for everything to access the net, then it won't help. The idea is to research whatever programs it's asking about and only then allow access. The firewall software built into windows is little better than nothing, but there are others. I've been partial to ZoneAlarm (there is a free version), but there are a ton out there.