PROBLEM SOLVED!
Just had confirmation that a new private beta has fixed this issue.
For the technically minded, something in the Intel/nVidia combo configuration was setting the LastDLLError property (i.e.; signaling that a DLL had returned an error code) after a call to SetWindowLong(hWnd, GWL_WNDPROC, lpfnNew). The subclassing routine was based in an old sample and structured in such a way that if LastDLLError held anything other than zero, it aborted the sub-classing of the window even if the return value of SetWindowLong indicated success.
No sub-classing, no notifications. No notifications, programs don't update, time is not announced, Internet communications don't work, plus a host of other related problems (I'm surprised how *anything* worked under these conditions).
So, if you have an Intel/nVidia combo and your Winstep application is misbehaving, please send me a private message.