Duo2 reset

First check to see what duo it is - follow this guide:
http://www.rnasguide.com/2012/01/09/how ... -or-nv-v2/

Then use the relevant boot menu instructions to do a factory default. Just google readynas duo v1 (or v2) boot menu and look at the Netgear knowledge base instructions.
You will need a disk in the nas when you do this and data on the disk will be wiped.
Once you have factory defaulted the unit the password will have been reset.
http://www.readynas.com/kb/faq/boot/wha ... ry_default

After you have done this I would suggest upgrading the firmware to the latest before doing anything else.

There is a large amount of information if you use google and/ or the Netgear manuals and kb.

http://www.readynas.com/download/docume ... 6Dec11.pdf

http://www.readynas.com/download/docume ... ept-11.pdf

Those are the hardware manuals for the v1 and v2. They have the boot menu instructions in them. There are separate software manuals.

I hope the unit is functional and you didn't pay too much for it. Users buying second hand are taking a risk.