I have an hp box with integrated ati graphics. It has an open pci express video slot. I am going to install an nvidia geforce 6200 video card and need to know the procedure for removing old the ati driver. Is it possible to edit the xorg file and change the video driver to 'vesa'?

The Nvidia install does the xorg.conf modification for you. Go for it. Mesa libGL* files get overwritten by both drivers, so try for an --uninstall or /uninstall on the ati, change the bios, add the nvidia and tell us what goes wrong.

I don't know what installer you're planning to use. Fedora and opensuse do packages, which is probably the way to go. Fedora or Red Hat have a detailed doc on doing this sort of thing, which you should read.

on opensuse please do NOT use the nvidia.run ( unless you know what you are doing -- you will have to manually do a lot of things )
install the nvidia repo file and use zypper to install the nvidia (propitiatory ) driver
or
use the default noeavau driver ( already installed but not used until you build the kernel mod )
see the opensuse nvidia guide
http://en.opensuse.org/SDB:NVIDIA

I was poking around looking for the xorg.conf file, but it looks like it was broken down into several .conf files. If 50-device.conf is the file where video card type is kept, can I edit the radeon entry and replace it with vesa or should I run sax2 instead, to change to a generic driver before inserting the nvidia graphics card? I noticed in /etc/x11/xorg.conf.d/50-device.conf and 50-monitor.conf that all the entries were remarked out with a '#'. If they are remoarked out, then where are the actual .conf files located?

the "50." file should be a "blacklist" file
informing the OS NOT to use the "noeavau " driver

Please use the "repo way" in the above link !!!!!!!!!

when you switch from AMD to a Nvidia card you will need to REBUILD the boot image

the repo driver WILL AUTO DO THIS!!!!!!!!
on the next reboot .

I opened the link and understand the 1-click install method. Since this is my first time swapping different manufacturer cards, I have to ask this question to avoid confusion:

1. After the computer boots, opensuse 12.2 will detect the new nvidia card and select the stock nvidia driver automatically?
2. I use the 1-click install which will install and configure the nvidia driver.

I thought that I had to switch from the ati driver to the generic and compatible vesa driver prior to the hardware install to prevent the os from puking. That was my thought in the earlier post.

I finally installed the nvidia card and opensuse 12.2 autodetected it and it is using the nouveou driver. My next step is the 1-click install for the geforce driver. Thank you for the help. I know that in windows boxes, the driver has to be rolled back to stock vga before installing a different card. Now I know that linux is a more robust operating system.