The easiest and simplest way to undo an accidental adjustment that went wrong is put things back to a state where things work, and go forward. Uninstalling and reinstalling doesn't necessarily erase all the settings that can carry forward between installs.
There is a free utility on Internet called DDU, Display Driver Uninstall. Grab the latest copy, bring the PC up in Safe Mode, use the utility to wipe out all traces of the previous install and settings, and then reinstall to the version you want. I would suspect the ideal choice would be to install the current driver as it has the latest bug fixes. This will allow you set the Eyefinity, etc. That should set your situation to rights.