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For more information on this, take a look at:
Wi-Fi: How to troubleshoot Wi-Fi connectivity
About Wireless Diagnostics
iOS and OS X: Recommended settings for Wi-Fi routers and access points
Best of luck,
Customer support related to Mavericks finally solved the problem. As suspected Airport was invisible to the computer. Lots of things were tried, but going to Preferences and picking Network and then picking Advanced.
The main problem seemed to be that nothing was indicated for "Configure IPv6". Once that was activated and and "Link-local only" were chosen. Things were set up to get things back to normal although getting the WD MyBook Live recognized was a bit of a hassle. The wireless printer was easy after that. I did not check your references, Mario but do appreciate your trying to help.