Thank you for the quick response. Yes, I would prefer to keep ALL the data that I've collected over the years. I suppose that there may be something in MY computer that is causing the problem, but it seems that the performance problem has just been getting gradually worse in the last year or so. Maybe I'll try to move the data to another computer and make sure I get the same issue. I think there are a total of about 3,000 tests. The delay in adding data is not just limited to adding a test, but any addition or modification is really slow. I've sent an email to support and would be happy to test the new release to see if there is improvement.
Again, thanks for your help.