can't reinstall PSE 2021, no such file

I continue to have problems with PSE 19. When I click on the Photoshop Elements 2021 application icon, the app opens to a blank screen. I tried downloading the program again, but after a download, when I click on the dmg file, I get an error that says "no such file or directory." Then, I tried to uninstall and reinstall, but the Uninstall application in the Support files folder won't open. What should I do?