Usually crash before main screen is a "missing master" crash, that means that a plugin (.esp) need a master (.esm) that isn't present in the data folder, but that doesn't survive reinstallation. However in this case it could have been the Archive Invalidation crash, however reinstallation should clear that up too.
Doesn't hurt to try: go to Steam/steamapps/common/fallout new vegas and delete the Fallout_default.ini and My games/Fallout NV, and delete Fallout.ini and FalloutPrefs.ini. After that use Steams Verify integrity of game cache (in library, right click on New Vegas, select properties, and select the Local Files tab).
If that doesn't work, uninstall the game, and run a registry cleaning program. It should clear all traces of New Vegas on your system, and return it to working condition.