Posted 08 August 2010 - 10:48 AM
I would hard-reset the router, clear the saved networks on your computer, and see if it can connect to the unsecured network at that point.
hard-reset = holding down the reset button on the back of the router for 10 full seconds.
to clear saved wireless networks in vista: control panel > (classic) > network and sharing > manage wireless networks > clear the list with minus sign in the middle of the screen.
If that works, setup security on the router again, while changing the name of the network, then try connecting to the new network name. if you can't, try a different kind of security.
If the pc wasn't able to connect to the unsecured network, return the router and get a different one.