In case you are not sure what a hard reboot is, there should be a small button somewhere on the router that will re-set it back to its original factory settings. That is what you want to try, assuming that you have tried unplugging and then plugging the router back in and that did not work.
I got better reliability from my Netgear router by disabling Send Logs.
Obliterate all of the target email info and the log will silently wrap when the size
is exceeded