Thakns, I'll try those two options tomorrow.
Do you have any idea what the likely problem is? I'm just not familiar enough with how all the systems tie into each other to make sense out of the symptoms. Not just slow running software, but also with internet. Though I suppose that since the browser software is in the hard drive, a bad hard drive might explain both symptoms.
I installed TotalAV because I was concerned that maybe the issue was malware or a virus. Is that a possible cause for the crash? I'd hate to get a replacement machine and by restoring it with Time Machine just reinstall what killed my current machine. When I looked at the Etre report I saw the following -
Major Issues:
Anything that appears on this list needs immediate attention.
Hard drive too slow - The hard drive in this computer is too slow.
Unsigned files - There are unsigned software files installed that could be malicious and should be reviewed.
Automatic updates disabled - Automatic updates are disabled. This computer is at risk of malware infection.
Apple security disabled - Apple security software is disabled. This computer is at risk of malware infection.
The "hard drive is too slow" would make me think the drive is dying. But I had no idea that Apple security software is disabled, and apparently the mac is vulnerable to malware. I'm afraid I don't know what "unsigned software files" are or how to review them.
I'd love to get a newer mac, but it looks like after the 2015 models getting one with a large hard drive is difficult to impossible. And I've been spoiled by that 3TB Fusion drive, both for the size and speed. If you have any suggestions for other options I'd love to hear them.
Sorry to keep on, I'm afraid I'm just babbling now. Thanks again for all your help, and if you have any other advice I'd very much appreciate it.