Long story short...I upgraded my computer from Windows 7 Home Premium to Ultimate for 64 bit. I don't want Ultimate, and would like to go back to Home Premium. I bought the laptop refurbished with Home Premium on it and no recover disk. There is a windows.old file, can I recover Home Premium from that file and install it? I want to reformat my computer so all data is gone after I reinstall Windows 7 Home Premium. Thank you in advance.