if the connection is good without the router, you might have a bad router or the firmware update might have broken what was ok.
my linksys router has the original firmware.
i'm not a believer in updates/firmware, just because uncle bill or the mfg. wave a flag, if the system is working.
i run 2000pro with sp4 only, no updates.
xppro, no updates before sp1, needed for a program, the program told me so.
98se no updates.
