Problems zorin os 17 pro and 18 core

Dear all;
I had a version of zorin os 17.3 pro installed on my laptop.
Last week i wanted to login to search something, but my password
didn't match. I tried to change the password via youtube, but didn't work.
after that i removed zorin os and tried to install the latest version.
After installing, the first reboot was fine. After that i wanted to check if this was realy ok, but at the boot the laptop froze. Right before the login screen it was hanging. What can i do to reintall zorin?
There is another problem with zorin, when i wanted to search the web with brave browser, the complete system freezes. Both with 17.3 pro and 18 core.
My laptop creds., acer aspire 7750G ( about 14years old )
intel core i5
AMD radeon
500GB SSD
8GB memory DDR3

Try it with disabled Hardware Acceleration. When it freezes directly to the Start, start the Browser in the Terminal with brave-browser --disable-gpu

Are secure Boot and Fast Boot in BIOs disabled? Does Your System run in Wayland or X11?

Maybe an older Kernel could work better for You.