22.04 - black screen after attempting to load some web browser pages (Chrome or Firefox)

Attempting to load certain webpages causes 22.04 to revert to black screen, with jellyfish logon screen following some 45-60 secs later. It can happen when just clicking on a google search page link. However, it has also ocurred several times when attempting to play certain vids through VLC media player.
This never ocurred with 20.04 - it was completely stable. If this can't be solved, I shall have to revert to 20.04, since this latest version is rendered almost unusable.
I installed 22.04 via an update prompt. My laptop is an Acer Aspire 5735Z, Pentium dual-core T3400, 2.16 GHz, 667 MHz FSB