Ubuntu freezes, crashes, can't close browsers, can't minimize

       Ubuntu 20.04.4 crashes opening any browser, firefox or chrome, chromium or Opera, can't unlock, after a certain time the screen then black screen, no screensaver, mouse locked. I have graphics GPU1 - AMD Radeon R7 Graphics - Main/Master/Integrated/Swappable, GPU2 AMD Radeon(TM) R7 M340 Linked/Discrete/Interchangeable. I removed old installation and installed. From scratch Ubuntu 10.04.4 LTS. What can I do to make it work properly? Some installation or configuration is missing ?. Everything is up to date. Thanks for your reply. The same thing happened to me when installing Ubuntu 21.10. VRAM1

512 MB
DDR4 933 MHz, VRAM2
4096 MB
DDR3 1000 MHz, RAM
8 GB
, CPU
AMD A12-9720P RADEON R7, 12 COMPUTE CORES 4C+8G
4 Cores.

Partition two operating systems, factory-installed Windows on computer hard drive, and Ubuntu mate on external hard drive. With Partition / , and Home, and partition swat. Thanks for your help