Got an old computer here but struggling to play the game without slight disturbance in frame rate. any mods out there that would allow me to lower the games visuals in general allowing me to play?

There's this mod that I use: http://newvegas.nexusmods.com/mods/45475/

It's not perfect, I still have issues with crashing/freezing, but it does improve performance so long as you don't have too many mods loaded.