At this point I have again uninstalled all Nitro and ran the clean-up. I have been trying to find and install the version immediately before the latest update of 13- it worked fine, but I cannot seem to find where you had all of the recent update files. I had to find a reversion previously for another matter. I have been a licensed purchaser of Nitro for many years and this has been extremely frustrating and expensive! My PC works great without Nitro installed!