GAME KEEPS CLOSING ITSELF

this is also happening to me too, except i am getting no errors.  this started happening to me after i purchased a few expansion packs.  i  am getting the lastcrash.txt reports but i have no idea how to read them and i dont play with mods.  i have uninstalled and reinstalled.  checked that my stuff was up to date and my game still closes out.  sometimes it will close immediately after opening and sometimes it will close in the middle of my game.  its horrible i