I loaded E-OS 5.1 on my 2015ish iMac (8G RAM, 1T disk) about a week ago. It has been running fine until today. I was notified I had nvidia driver updates so I installed them. After installation, it would boot normally but would freeze up at random times. After about 4 or 5 times of a hard, power off reset, it now boots to the login screen you get when it goes to sleep. I enter the password and the screen goes blank for about 5 seconds and then comes back to the same login screen. Any suggestions? I'm afraid the same problem will recur if I re-install. Thanks!!!