Hard reset D-Link DIR-300

Factory reset (Hard reset) The reset button/hole is located on the back panel – to the right. Power on the router and use a paper clip or another sharp object to press the button down and hold for 10 seconds. Release. Wait about 30 seconds for the reboot process to finish.
Firmware Firmware link
Default username admin
Default password [leave blank]
Default IP address 192.168.0.1