There is several ways.
* You can pick TUI from Lilo if you have that option.
* You can press tab at the Lilo boot screen to get a Lilo prompt. Once you get there, start your system using a label followed by 2 (the runlevel in which you wanna boot, we use runlevel 2 for a text mode console login). The label is usualy VectorLinux, Lilo will tell you what are the options. So, you would have to type "VectorLinux 2" at the lilo prompt.
* Once X fails and you get a blank screen, you can try the Control+Alt+F2 shortcut for getting a console login.
* You can use the VL install cd for booting your system. There is instructions in the CD for doing that. Shortly, you have to type linux root=/dev/<root_partition_of_your_system> (something like sda1 or hdb2)
* You can boot Knoppix and mount your VL partition. Get a console and do "mount -t auto /dev/<vl_root_partition> /path/to/mount_point". The mount point has to be an existing directory. You can create one with the mkdir command. Traditionaly /mnt is used, so "mkdir -p /mnt/vector" would do it, and then "mount -t auto /dev/<put_vl_partition_here> /mnt/vector". Once you do that, your xorg.conf can be accessed in /mnt/vector/etc/X11/xorg.conf
I think I have listed all your options, from the easiest to the most difficult. Please post back here if you find any problem.