Alternate Install Method using Emergency Room Web Interface

Setup your PC with static IP on 192.168.0.0 subnet.
Make sure the PC has the following two files:
dlink-revb-factory-webflash.bin
dir300-revb-ddwrt-webflash.bin (or the 600 equivalent, depending on whether you have the 300 or 600)
Open your web browser and get it ready to connect to 192.168.0.1.
Press and HOLD the reset button on the router and connect power. Hold the reset button for about 3~5 seconds, then release.
Connect the browser to http://192.168.0.1/ . The Emergency Room Updating Firmware screen should display.
Browse to and upload the first image file, the 'factory' one.
When you see the message "IMAGE UPLOAD SUCCESS", the flash will begin to be erased and re-written.
Wait until the power LED turns to solid 'Yellow'. At this point, the initial dd-wrt image has been written to flash, the device has rebooted and is running.
Change the IP address of your PC to the 192.168.1.0 subnet. Use your browser to connect to the router at http://192.168.1.1/
The DD-WRT screen should load. If not, you did something wrong. Go back and try again.
There is a report that "emergency room web interface" may not support IE8, so if it does not work then try another browser: "Note that Internet Explorer 8 did not work for me on the emergency room web interface. It gave me a general page view error during the firmware upload. I had to use another browser to make it work (I used chrome but fire fox would probably work as well)."