SOLUTION. The PDF viewer hang issue resolves easily
PDF-XChange Editor pro v7.0 includes a detailed configuration facility within the path File > Preferences > File Assocations form.
- Set "Register NP-plugin for other browsers" to "Yes"
- Set "Preview Handler for PDF files" to "Yes"
- Set "Thumbnail Handler for PDF files" to "Yes"
- Hit [Apply]
- Restart the machine.
I had performed steps 1-4 previously, without affecting the outcome. The Restart did the trick. Thank you for your help! Bruce Chitiea, SafeSectors, Inc.