Unity editor keeps crashing on startup

I have just recently installed unity 5,I signed up made a new project,but as soon as I tried to open it the editor would crash.Now before you suggest holding "alt" keep in mind that I've never even managed to open a project so every time I run Unity I get the option to choose which project I want to work on(which doesn't really matter because the editor crashes on startup no matter which project I select,even the example project)