This did the trick for me (found from
While holding down the reset button, plug in the power cord. Hold the reset button for 30 seconds.
Somehow my admin password (normally root/admin) has been corrupted. After installing dd-wrt, I turned off 802.11x and clicked 'Apply Settings'. Since then, I can no longer log into the admin interface because my root/admin login pair won't work. Also, since this is a fresh install, ssh is NOT enabled. I've tried holding the reset button for 20 seconds, and that seemed to re-enable 802-11.x (so clearly it did some level or restoring default settings). However, I still cannot login.
Any ideas are appreciated...
This actually install the default setting of the router. Good to know that you problem has been resolved. It may help others also.