Well, it works now, not sure why, but things are back where they should be.  Based on your wordy posting above , I downloaded the latest version of SSMSE.  Once installed, I fired up the Activity monitor and watched the Process Info for a bit.  I kept noticing unusually long times on two sprocs: GetSchedule and GetScheduleNext.  I pasted them into a SQL window and sure enough they were taking about 10-20 seconds to run.  So, not knowing what else to do, I started deleting the records in the ScheduleHistory table.  I kept getting a "data has changed since last read on row nn" warning, so I skipped those and kept deleting.  When I got to the end, all that were left were about 10 records that said "Site Log Purge failed" in the LogNotes field.  These records were all quite old, so I doubt very much there were any changes still going on.  So there was something odd about those records and I had to delete them one at a time.  Once they were gone, DNN performance, well SQL performance is back where it should be.

Hope this helps someone in future.

Thanks for help.

Weezy