Yes, Lightroom 5 is still available for download and use (here for instance) if you need it.
However, with Lightroom 6: Make sure you have updated the software to the LR 6.0.1 version which came out recently – it contains some bug fixes, particularly around start-up...
Check Help menu > About for the version, and Help > Updates to get the latest if necessary.
Thanks, but that didn't work. First, I got tricked into signing up for Creative Cloud, by following what was deceptively presented as a way to access LR5, then I saw the direct link down at the bottom and got an "Access Denied" page. And yes, the version the is crashing on my system is the new one. I'm very dismayed. Thanks for trying to help. Is there any hope? Thanks.
I may have spoken too soon, as I actually had the earlier, non-updated version running each time. Fingers=crossed now. Thanks!
OK great Joe... So which version(s) are you running successfully on your system now – LR 6.0.1, LR 5, or both?
It's 6.0.1. I was mistaken earlier because I had assumed that, since I reinstalled from a new download (using the link provided upon purchase of the upgrade), that the download was the updated version. But then when I re(re-re) downloaded for the latest (current) attempted install, I saw that the download was in fact 6.0 and I immediately upgraded. Now I am hopeful it will be stable. So hopefully I won't have to go even try to go back to an earlier version. I saw a lot of people seem to he having/have had crashing upon opening issues.