I have an old machine with a GeForce 7800 GS (AGP), but some of my older games are not compatible with this card's current drivers.  I was thinking about installing a second card, a GeForce FX 5500 (PCI), with older drivers to solve this compatibility problem.  Seemed to be a good idea, since lots of people have an AGP and PCI card for a dual monitor setup.  Then I remembered that Nvidia bundles all their video cards together under one driver release.  So is there a way to keep current drivers installed on my AGP card, but install my PCI card and make it use, for example, older Forceware 77.77 drivers?  
 
I don't have the PCI card yet, so I don't know if installing separate drivers will be a problem or not.  If it matters, this machine can dual boot into either 98 or XP, but I don't want to use older drivers in 98 for my AGP card either.  Hopefully someone out there has already tried this and knows if it's possible to do this.

by default the latest drivers will load up for both cards.
To solve this problem buy a DAMIT video card then you won't have conflicting drivers.
 
Anyone else done this?

I've had a All-In-Wonder 128 and a Geforce 2 co-exist in the same system, that was a while ago but I had no problems.

It may be simpler to buy a used PC from somebody or some store.
 
One of the local stores in my area had a big sale last summer: CAD$225 for a refurbished PC with a Pentium 4 and 1 GB of RAM and 40 GB of disk and a DVD-RW. I forgot what kind of video card they had, some AGP 4x cheap junk. For a 5 year old game that's a dream machine.  
 
Add a KVM switch so you don't need a new monitor/mouse/KB and you're all set
 

 
I've considered this.  I actually have a KVM switch and another computer (a creaky old Dell) from 7 years ago.  Thing is, rather than use space for this tower, I would much rather fill it with a new machine I'm planning that will be installed with Vista, SLI, and all the works.  I could use it for new games like Bioshock, Crysis, Hellgate, etc.
 
I have a similar arrangement right now with two sound cards.  For modern games I use the X-Fi, but for games that like an older SoundBlaster, I can switch cards in my audio properties to the SB 16 PCI.  Both live harmoniously together with separate drivers.  But for course, the PC actually allowed me to install these cards with separate drivers.  
 
Nvidia is a whole different circumstance since all of their cards actually use the same driver release.  And I'm a little apprehensive about installing drivers that were released before my AGP card was ever made.  If the AGP card tries to use those, I'm concerned it could damage the card.  Of course, if there's a way to tell the AGP card which drivers to use, and then tell the PCI card which drivers to use, my problem is solved.

I don't know if this will work but try removing all video card driver first before installing the PCI one.  Then install the older Forceware driver but install them in a different folder than the default NV one.  Restart the machine.  Now install the new Forceware driver in the default location.  Make sure the 7800GS recognizes the new drivers.  Check to make sure the old Forceware drivers are still in the different directory.  Now install the PCI card.  When you boot up and Windows says it has found new hardware don't let it install any drivers for it.  Go to the Device Manager and right-click the display device that has a big yellow question mark by it and click properties.  Click update driver and point Windows in the folder where you installed the older Forceware driver.
 
I have no idea if this will work.

OK, that sounds like an idea worth trying.  
 
Actually, just to give a little more background, some of my older games require a video card that supports 8-bit palletized textures.  Nvidia stopped supporting this with their 6xxx series.  So PC versions of Metal Gear Solid and Final Fantasy 7 & 8 will not run properly on my GeForce 7800 GS.
 
As long as the hardware in the video card supports these older graphics, I'm sure some tweaking can be done with the drivers if necessary.  Hopefully I can get this to work.  

You could easily pick up PlayStation versions (FFVII being the exception) of those games and emulate them on your PC without having to worry about two different cards.  I emulate FFVIII and IX and they look rather well.

Completely remove all the video drivers currently on your system. Install your old card. Boot up and install the drivers for that. make sure you can use it for the games you want. Shut down. Remove old card, install the newer card. Boot up. Install driver for that.  
 
 Sometimes there will be conflict, sometimes there won't. Trick to it is to install the old before the new. Good luck.
 
I've also had no problems running both ati and nvidia drivers at the same time.

If your talking about where to extract the video card driver install files, this will make no difference.  You cannot choose where to install drivers, they get installed where Windows wants them.  In fact you can remove the extracted files after installation (I always do).

That's not what I meant.  I'm not talking about the extracted files from the downloaded .exe
 
I'm talking about where the program asks you to install them like C: Program Files Nvidia, etc.  I understand Windows installs the driver in the system folders, but the driver file should still be located in the directory where the Nvidia program installs.  If he installs them in separate directories (one non-default, the other default), when he install the latest drivers it won't overwrite anything.  He then might be able to "point" Windows into the older driver (non-default) folder by telling Windows where to look for it after he puts the PCI card in.  At boot up it will say "New Hardware Found", he'll have the option of telling Windows where to look for the driver for that card.
 
Like I said, I don't know if it will work and you could very well be right but it is worth a try.

Gottcha, misunderstood the first time.  But IIRC the "default" location for any driver revision is in a subdirectory by the driver revision #...so they should not overwrite each other.

That part of what I'm not sure of as I always uninstall old drivers and get rid of the folders myself.  Like I said, I'm not sure it would work.  Most likely if it does, the OP will not get any kind of control panel interface for the PCI card but they would at least get the card to operate using the driver they wanted.
 
Then again, I could be full of it (actually I'm pretty sure I am).  Unless the OP returns, we'll probably never know.

Yeah rennervision, where are you?  Did you try it?  Did it work?

Hi everyone.  I got around to trying this yesterday, and here's what happened:
 
First, I can confirm that my new Geforce FX 5500 PCI card does indeed support 8-bit palletized textures. I installed the card two slots below my Geforce 7800 GS AGP card and used 77.77 forceware drivers. It passes the Final Fantasy 7 & 8 config tests with flying colors and when I force 4x anti-aliasing, FF8 looks great.  
 
However, these drivers are not compatible with my AGP card (not surprising, since my card didn't even exist when these drivers were released). So when the hardware wizard detected my AGP card, I directed it to a folder I saved containing the newest 162.18 forceware drivers. These files are then automatically installed in my windows/system32 folder.  
 
So after I reboot, unfortunately, both my AGP and PCI card are now using the 162.18 forceware drivers. Now the FF7 and FF8 config tests on the PCI show I failed for paletted textures.  
 
Two odd things I noticed: (1) Metal Gear Solid plays fine in hardware mode using the 162.18 drivers on my PCI card. I've never been able to play the game at high resolutions on my AGP. So that's one success at least.  (2) I've verified a GeForce 4 Ti600 AGP card with 77.77 drivers supports palletized textures - and if I upgrade the drivers to 93.71, the card still passes the FF 7 & 8 config tests. But if I use forceware 93.71 on my current setup (since these are compatible with both my PCI and AGP card), my PCI card goes back to failing the tests!
 

 
Honestly, part of the reason why I'm doing this is just for the satisfaction of knowing I created a workable solution for it on the PC.    But I do appreciate the suggestion.  I have emulated Playstation games on my PC before, so I realize that's an option.  For some reason, I could never get the PS version of Metal Gear Solid to run correctly (tried all kinds of different video and sound plugins), so I was kind of forced to solve the MGS problem without an emulator.  The new PCI card does seem to work around that issue.

Well it was worth a shot.  All is not lost yet though.  You could try rolling back the driver now for the PCI card in the Device Manager.  If you removed all of the previous nVidia drivers before trying my theory out, the only driver for it to roll back to should be the 77.77 one.  Not sure if it will work though.  It may try rolling it back for both cards.