I had a problem whereby my COD would only work with 52.16 Nvidia drivers, as everyone is aware this meant no RTCW until rolling back to the 45.23 drivers due to a conflict with Punkbuster.
The solution - (stick with this it's boring)
Load up the 45.23 drivers.
Click START.
Right click My Computer.
Choose Properties.
Choose Hardware.
Choose Hardware profiles.
Click on default config and rename it "RTCW Config".
Copy it.
Click the copy and rename it COD Config.
Reboot.
Now as you boot up you should be given the option to choose between configs choose the COD config.
Then install the 52.16 drivers.
Now when booting if you want to play RTCW choose that config or if you want to play COD choose it's config.
I found that on my system choosing any config let me play both and I've no idea why but i don't care because now I'm sorted.
Whoo hoo !