My father and I want to secure his wireless home network but we're running into an odd issue. He has a Linksys WRT54G wireless router and according to some reading I did, the best security mode for home wireless systems is WPA. His router can be configured to support it just fine using the administrative panel but his Averatec 5110HX laptop (bought roughly three years ago or so) doesn't seem to support that security mode. It simply cannot be chosen from the "Network authentication" section in the wireless network's properties on the laptop.
My question is, is there some other way to enable this or install it somehow?
Any help would be appreciated.