My power went down and when it returned, I could not access the internet via my Cisco Linksys router, model WRT350N. Windows diagnostics returned the subject error message. After 12 hours of researching and trying a number of "fixes" suggested on many forums, including this one, I resolved this problem by simply updating the firmware on the router. I'm guessing that some Windows Vista update caused an incompatibility and when the computer and the router were rebooted after the power outage, the incompatibility was activated. Anyway, I'm adding this to assist others so that they don't have to spend the amount of time I did resolving this frustrating problem.