How can I fix fallout new vegas launch crash?

I am playing fallout new vegas using steam and when I start the launcher and select play it goes for a second and an error message pops up saying "fallout.nv has stopped working and then quits" I tried deleting all my mods and uninstalling reinstalling the game etc and it still does the same. The internet says to verify game file cache I try that and it says every time that one file is doing something and will be removed but that never happens. the internet also says to right click the thing from the start menu and click properties and run in compatibility mode but in properties there is no compatibility tab help IVE BEEN STUCK FOR TWO DAYS NOW!