In December or January, I decided to move on to Lubuntu 18.04 LTS (Bionic Beaver). I did a fresh install, formatting the hard disk that had previously had 16.04 LTS (Xenial Xerus). After that, I had several busy weeks with no time for Second Life.
When I finally tried to return, nothing happened. Neither my Firestorm viewer (downloaded as Phoenix_FirestormOS-Release_i686_220.127.116.11680.tar.xz) nor my Second Life viewer (downloaded as Second_Life_4_0_8_319463_i686.tar.bz2) can be started any more. There may be a faint flash on the screen, but nothing more.
I removed my Firestorm and re-installed it. Nothing changed.
I have tried to find reports on known issues, but all of those seem to revolve around 64-bit Ubuntu causing problems. Mine is 32-bit, I have checked.
One forum message I read somewhere suggested that my Lubuntu might be missing certain necessary libraries, but nobody else has mentioned that idea anywhere else. Have there been such major changes between Lubuntu 16.04 and 18.04?
I have had quite limited time to ask around, and getting help appears to be difficult. No, I am not expecting a quick fix (any more). More like, I am asking whether anybody has any idea what is going on and could provide reading suggestions or something. No, I am not good with computers, but sometimes I get problems solved regardless.
Before this, both the Firestorm viewer and the SL viewer worked decently on my computer... mostly. There have been very bad crashing issues at least twice, and seemingly nobody has ever described the exact same problems anywhere, but they have always gotten fixed within weeks, or within a couple of months at most. Nothing else has ever excluded me as totally as this issue now.