I am trying to enable WEP or WPA on the WRT54G. When I login to the router and goto the wireless security tab, I see both listed in the drop-down. Whenever I select one, the page defaults to "disabled" and it never asks me to enter the key. The security never enables and the network is left open.
Ok first try reseting the router back to factory default settings, and try again if that still does not work I would suggest getting the current firmware for the router and upgrading the firmware in the router. The best way to make sure you get the right thing put in. ftp://ftp.linksys.com/FatWire/LinksysUpgrade.exe Make sure that you never perform a firware upgrade wirelessly. Always be directly connected to the router or you will turn it into a 50 dollar paper weight.
Vista Ultimate 32 Bit AMD 64 X2 6400+ Black Edition 4BG RAM 1.18 Terabytes Of Hard Drive Space Acer 22inch Widescreen LCD Nvidia 8600 GT PCI E 512 DDR3 WRT54G Router Netgear Gigabit Switch Motorola 2210 Modem
Try a different computer and see if the problem is the same. If it is, then just like PCTECHPAUL suggested, update the firmware of your router and make sure you are running a wire from a computer directly to your router. Also double-check the exact model and version number of your router (Usually its underneath the router:which is by the way, A VERY SMALL PRINT)