hi give this a try “How Can I Fix Mouse Acceleration Problems?” The game’s mouse acceleration may be annoying you. You’ll have to edit a few INI files to fix this. 1. Make sure the game / Steam is closed 2. Navigate to My Documents\\My Games\\FalloutNV and set “Fallout.ini” and “FalloutPrefs.ini” to NOT Read-Only (right click each file -> properties -> UnCheck “Read-Only”) 3. Add the following to the [Controls] section of each file– fForegroundMouseAccelBase=0 fForegroundMouseAccelTop=0 fForegroundMouseBase=0 fForegroundMouseMult=0 4. Next navigate to “C:\\Program Files\\Steam\\steamapps\\common\\fallout new vegas” 5. Set “Fallout_default.ini” to NOT Read-Only and add the same lines above to the [Controls] section 6. Next navigate to “C:\\Program Files\\Steam\\userdata”. There will be a folder here with random numbers as its name. Open it, then sort by last modified (right click folder -> “arrange icons by” -> “last modified”). Open the MOST RECENTLY modified folder that is NOT “config”. 7. Make sure “falloutprefs.ini” is NOT Read-Only, and edit it just as you did with the previous INI files. from ; http://geekmontage.com/texts/fallout-new-vegas-game-fixes-crashes-audio-issues-lag-saving/ greetz