An easy way of getting this, and every Achievement, in Fallout 3 PC, is by pressing the ~ button on the main menu.
On the bottom left of the screen a | sign will appear and you can start typing,
all the way up to,
This and every other achievement will instantly pop for you.
Also, in NO way, shape or form is this any version of hacking or gamesaving. Your gamerscore will NOT be reset nor will you have to worry about the TrueAchievement Investigation Team labelling you as a cheater. This is a feature that was intentionally left available to the public in this game by the developers. Why they did this? I have absolutely no idea. Maybe this is the one time developers tossed achievement connoisseurs a bone for all the times they have created near-impossible achievements, or maybe they forget to turn this off before publishing the game.
As typing it's begin November 2013, and Microsoft already announced that GFWL will shutdown soon, rumours are begin 2014, with that all achievements for GFWL will become unobtainable.
So if you wish to give your Gamerscore a quick boost, 1550G in about 20 minutes of typing, or mop up the last achievements that you need, do it now before it gets shutdown!
The following are the minimum system requirements needed for Fallout 3 (PC).
Operating System: Windows XP® , Windows Vista®
Processor: 2.4GHz Intel® or 2.4GHz AMD
Video Card: 256MB NVIDIA® GeForce® 6800 or ATI Radeon™ X850
Hard Drive Space: 6GB
This is a great website to see if you have the minimum and/or recommended system requirements needed for any PC game.http://www.systemrequirementslab.com/cyri/analysis.aspx