I finally got to the bottom of my perplexing computer freezes (HPE h9-1135 Phoenix). The Radeon HD 7790 video card has problems with the Catalyst drivers for 7000 series cards and I have found that I am not the only person with this problem. I am now crunching using Linux Mint 17 and the native drivers. If I load the proprietary AMD drivers, it will freeze. I found some Windows drivers specifically for the video card (14-4-xp32-64-dd-ccc-pack3.exe). but I would have to load Windows again to test them. I'm working on an AMD R9 deal with one of my grandsons.
I have a grandson (13) in Japan and learned yesterday that he bought himself a gaming laptop: https://www.asus.com/ca-en/Notebooks_Ul ... OG_G750JH/
. That boy gets a lot more money than I ever gave his Dad!