On Aug 29, 2018, at 02:57, Dhanasekaran Balakrishnan <dhanasekaranbioinfo at gmail.com> wrote: > > Yes nvidia driver is installed in the computer. I am not sure how my > colleague did this and presently he is not in my lab. You will need to fix the nvidia driver. I suggest using the packages from elrepo.org if you aren’t already. Most likely you rebooted into a new kernel that didn’t have the nvidia kernel module available. — Jonathan Billings <billings at negate.org>