Grub - Boot menu is not shown by default. you have to hold down your shift key after post to get it unless you have done something the system like repair a grub boot config from a livecd or the like. Your problem is not low level it is well documented, driver installs reboots to a scaled driver not loaded but restricted gui, in the old days we would at that point sudo nvidia-xconfig and reboot to a full scaled 1920x1080p desktop and then edit the xorg.conf to what we needed. Now it's not like that issuing sudo nvidia-xconfig causes a black screen but the system is still running as you can access it from a putty (ssh) session across the network. All this is just FYI for you. As a new user I suggest doing the above in my post only, you can get yourself in deep doo-doo pretty quick issuing commands from all the posts you read across the internet.