Most users use the Nexus Mod Manager in order to use Mods on the game which is a modding application that allows users to apply a lot of mods to the game.I had to get the Fake Windowed Fullscreen mod to prevent the game from crashing if I just hit Alt+Tab. You need to do some research on Google or in other gaming forums to find out the one which is best for you. It is HIGHLY RECOMMENDED that you install the fixes for Vanilla New Vegas: New Vegas Tick Fix and New Vegas Anti Crash.I couldnt have been more until the game starts crashing ONLY when pressing the B button on my controller.