I used to play Fallout, beautiful game.
It has always ran very stable on my Windows XP.
It seems like you have enabled or disabled an input device.
Input DeviceI donot understand why Fallout would show you that error, I suggest you download the latest patch from
Interplay and undo any changes you have made to your system.
Reinstalling the game is also an option. However, be certain to make backups of your savegames first.
Perhaps you can get help on the Fallout forums as well.