Did you run Envy from the menu? You can install the Nvidia drivers using this application.
If the horizontal sync / vertical refresh are off then there is xvidtune command.
Open a terminal and run the command
xvidtune
Click cancel in the box that pops up.
Now you have your monitors refresh rates in terminal.
Use them in your /etc/X11/xorg.conf
Open a terminal and:
Find where it says section montor and add the h-sync and v-refresh from the xvidtune command (see following).
Section "Monitor"
Identifier "Generic Monitor"
Option "DPMS"
Horizsync 30-70
Vertrefresh 50-160
EndSection
When you bork the xorg-config file you can reset is. Try it on the install the isn't working if you can get to a tty screen (Alt+F1). Login and then type in:
sudo dpkg-reconfigure -phigh xserver-xorg
Note: this can be done from terminal if you can get to one.
I'm not sure what you mean by getting rid of the un-useable one, but if it's in a separate partition and you don't need any of the data you can reformat that partition using gparted. However, let us know what partition you installed on - post you /etc/fstab file.
Don't know about my space.