In your post you said that you think that the compile process of the nvidia driver went fine, but you can't use sax2 to finish the configuration of X. Then I suggest you to try to configure by yourself the file /etc/X11/xorg.conf.
Once you are in console, login as root and then use your favorite editor to open the file /etc/X11/xorg.conf.
NOTE. If you plan to make changes to this file, before editing it make a backup of this file:
cp xorg.conf xorg.conf.backup
Review carefully the following sections:
# Load "dri" Comment this line
# Load "GLcore" Comment this line
HorizSync ??-?? Put the horizontal frequency of your monitor here
VertRefresh ??-?? Put the Vertical frequency of your monitor here
This is the basic configuration. In case you have problems with the driver, you can change it temporarily to "nv" or "vesa", until you can have the nvidia driver working. Also check the keyboard and mouse sections.
If you can't start X, review the file /var/log/xorg.0.log in order to see what went wrong. The lines that start with (EE) are the lines that you must read carefully.