>This app has been running for several years on Win 7 machines with no problems.
>On a new Win 8 machine DateTime.Now.Date returns 2014-03-21:23:00 when it should return 2014-03-22.
>The time on the machine is OK and the time zone is correct.
>It consistently places the date one hour before midnight on the prior day.
>Code works fine on other Win 8 machines.
>Any suggestions?

You've shown two different formats (neither of which include seconds). How are you viewing these values and what *exactly* are you seeing ?
Also they look more like SQL datetime values than .NET (unless you're using something like DateTime.Now.Date.ToString("u",new CultureInfo("en-US"));)

If they are .Net then what is currentculture and what do DateTime.Today, DateTimeUtcNow.Date and DateTime.Now.Kind show ?