Switching graphic cards

If they are identical (same model) you shouldn't need to touch anything.
If they are diferent models even of the same brand, you would need to reboot on safe mode, switch graphic controller to the default one and use DDU (display driver uninstaller) or uninstall the graphic drivers from control panel (windows), pass ccleaner to remove any traces, reboot and install that specific new card driver (you get them from the page, be it nvidia or amd)

>>56228282
Name the card.

Windows can display just fine without dedicated drivers since Windows XP.

NvidiaGeForce GT330 and NvidiaGeForce GT630

>>56228792
Might be the same game ready driver or whatever they call it.

>install
>Gentoo

>>56228282
You *should* just be able to swap the cards, and then download and install the drivers. The display may be slow and/or have a shitty resolution until you install the correct drivers, but it still should be functional enough to let you download the driver. If, for some reason, you get no picture at all after installing the new card, only then should you try installing the new drivers first--the reason being that the correct driver for the new card may not even install if the installer detects that the card is not inserted.

TL;DR: try installing the new card before installing the drivers.

OK guys, i'll try, gimme some time, thank you very much for your time!