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I am having intermittent problems with internet access; often in the middle of a session.  The message says that "the server at (target) can't be found because DNS lookup failed.."

I've tried the various solutions offered in the error message (i.e., reload, check connections, disable network prediction), but don't know how to implement the possible solution to "Allow Chrome to access the network in your firewall or antivirus settings."  Obviously, I'm not very computer saavy.  Will someone please explain this to me?