and delete these three files from internal memory (with WiFi OFF)
Might also try deleting WiFiUnsecuredNetworkDB-WPnl too. All four of those have the same creation date on my LD.
Exit FileZ then do a soft reset. Then turn on WiFi and try to connect. All your old networks and keys should be gone.
If that's successful, do a hotsynch so the new files will replace the old ones on your desktop computer.
Would be nice if there was a WiFi database editor app to *completely* remove network info for WiFi spots you'll never ever connect to again, without having to completely delete the entire database. (Like Classic Mac OS where the only way to remove network shares that were not available to connect to was to trashcan the whole preferences file they're stored in. Nobody ever wrote an app for that either.)
P.S. Got a CF in yours or still the someday-will-die Microdrive? I bought a SanDisk Ultra II 4gig on sale for $24.95, and since I didn't have an IDE to CF and none of the USB to CF readers I had would play nicely with any utility to alter its CHS values and DD a ROM image to it, I sent it off with $25 and $2 return shipping to have it done by some place that normally sells cards ready to plug in, for $90. Since my LD was a birthday gift, $57 is all I have into it.