The Fallout series as all we know and love takes us back in 2008 to New Vegas (a spin-off and loose sequel tied to Fallout 3). Since the launch the game us moved to Steam from original Games for Windows Client. Activate the game through Steam first and then insert the DVD and install it through disks. You may be prompt to download 300 MB patch files.
If you're fan of old school RPGs then belive me guys this game will take your breath and take it to another world into an post-apocalyptic world where survival, friendship, love, hate, revenge are all the things left. This game takes more than 150 hours to complete as there are tons of missions and side quests and a massive large open world to explore.
The most disappointing thing is that this game along with Fallout 3 released same year in 2008 was banned in India and pulled out from sales due to some silly reason and there's no way to buy DLCs for this game as this is not available on Steam for Indian store. However you can still buy DLC codes from third party sites that sell steam codes.
Overall it's a great under-rated game.