I have had Ubuntu for quite some time now and recently I have been having some problems with the generic drivers that have been causing kernel crashes and so many things went wrong that I can't fix anything because every problem keeps me from fixing the others. I discussed the problem about the generic drivers here: Ubuntu 18.04 having kernel panic on boot and I never found a fix. Now I have decided that the easiest thing to do will be to boot Ubuntu fresh from a CD onto the computer in a different partition and then delete the old one. Now, I am wondering if there is a way to transfer my personal files from the previous partition (my personal files are fine despite the problems I have been having) into the my new boot as I am installing it. Is it even possible or would it pollute my new installation as well? Is it better to transfer the files manually after the installation? I also have Kali Linux and Windows 10 running on the same machine.
I would do a backup to the cloud or external media and do a complete new install if you copy your config files from your old install to the new one your more than likely going to bring those problems into the new install. So I recommend against doing that.
Do the Clean install an overwrite the old install completely. Just MHO.