Bought a "new" Wii after Christmas and hooked it up only to find that it is actually used.
Is there a way to do a master reset to restore it to new settings or do I have to take it back?
Yes, you can "scrub" the memory clean so it's restored to the factory settings. Here is a link to instructions on how to do this:
Go to Wii options, Wii settings, then go to page 3. An option will say Format Wii system memory. Select it and say yes. It will restore it to how it was originally bought. However, it will erase all save data.
I bought a used one with parental controls, is there anyway to remove that?
More information at the above url (and copy&pasted below), but you'll first need to get a "Confirmation/Inquiry number" and then call Nintendo's 1-800-255-3700 (6 am ~ 7 pm Pacific, everyday) Customer Service number, and one of the service representatives will give you a "Master Key" code to unlock the Parental Controls.
Applies to: Wii, Wii mini