I am going to buy an SSD to only put operating system on, but still, have my old HDD as a large file holder. When I built my PC, I bought windows 7 and upgraded to windows 10. The only forum I could find about this is here: http://www.tomshardware.com/answers/id-3369225/installing-SSD-existing-hdd.html But I am afraid to do a fresh install of windows 7 because I do not think I can upgrade to windows 10 anymore. Please help me with this.