I can't upgrade any software. I always freeze at some point during "writing files". I am reluctant to reinstall the original software as I am yet to find option for saving existing files/data. Do I really need to do this (reinstall) or should I stop being stingy and just go and buy another hard drive. Computer is less than 3 months old so I am fairly unhappy to spend money when I think Apple should come to the party. Please advise.