My nVidia GeForce 8800 GT broke. I bought an AMD 5770 to replace it. I cant log on to my computer to remove the nVidia driver because I cant see the screen with a broken GPU. Without doing so, is it safe to install my new AMD card? Will Windows get confused and attempt to use the nVidia drivers on the AMD card, thereby screwing up my new card?
Generally you can install the AMD drivers with little or no real side effects, the system will not get confused and try to use the wrong drivers.
I have literally just gone the other way with a machine, from AMD to nVidia and I literally just took the AMD card out, put the nVidia card in and then installed nVidia drivers. I haven't yet uninstalled the AMD drivers, but I intend to at some point. The machine works fine and everything works as expected with both sets of drivers installed.
The drivers that get used for a device are determined by how the device reports itself to Windows and Windows will load drivers that report support for the device in question, it will not load AMD drivers for an nVidia device or vice versa.
At worst all you should have is some useless files in your system (the nVidia drivers) just sitting there taking up space and doing nothing. You should be able to uninstall them after getting your new graphics card up and running.
Your system will probably boot, but I wouldn't recommand it.
There's a windows safe mode, where you can navigate through a minimalist graphical interface. If you don't have any screen output on your motherboard, your GPU must be well enough to at least display something on your screen. To access safe mode, press and hold
Get the new drivers and DriverCleaner (free edition) or DriverSweeper and put them on a thumb drive (for example). Then go into safe moden uninstall the drivers, and clean the rest with the aforementionned software. Install the new drivers, reboot and profit !