Hi Paul,
your problem seems to be similar to one i encountered after putting
too much ampage through my linksys router. There is an ampage
regulating diode in the router and if overloaded will destroy it or
ruin its callabration . The only way i got my router to function after
overloading it was to keep the ampage constantly high and above the
recomended ampage.

The router now works fine but overloading it is not recomended and it
shouldn't be left unattended.I recomend replacing the router.