My macbook stopped functioning when trying to open photoshop or MS office programs last night. Today, I tried updating the software to see if that fixed it. Now, when I turn it on, it freezes on a blue screen. I have tried to start in safe mode but it simply flicks from the blue screen to the default pinkish galaxy background image. I can't get it to do anything else. I have most of my important files saved so I really am just interested in resetting it to factory settings and being done with trying to save files. How do I do this without a disc?