Fab

So I got this yesterday and I made an animation. I saved it as movie and then closed it. Next day I go to my computer to check on my animation and when i go see in the folder, it desepeard!! i search EVERYWHERE. I was ok and made a other one. I saved it and when i went see it, it wasen't there! I made 2 more animation that took a loong of time doing and now every time I crash. I save it and it crash , I go see if it's there, it's NOT. please help, it's gonna be my 5th try to make a long animation.