why is it every time i try to start new vegas i get "This game is currently unavailable. Please try again at another time." ive been trying to play the game for 3 days and i get the same thing every time

how do i fix this?

Well you could always re-install the game, which works for Team Fortress 2. However, if that doesn't work, either post on the official Steam board or go on Ask.com or something. But it should work and if you uninstalled it correct, I believe you'd still have your mods and fallout mod manager available when you re-install it.