Hi everyone! I have a MBP 15'' mid 2010, the osx that what installed in the beginning was Snow Leopard. I've been using it for all these years, and I've been downloading all the new versions until today's one (Sierra). But my computer definitely isn't working well with this new os. I would like to go back to a previous os... what I really would like is to go back to Snow Leopard... but if it's to "El Capital" or "Yosemite" it would be also fine. I've been checking how to do it.. but so far I couldn't find anything that works for me. I don't have a time machine backup to go back to any previous os x version, and all that I found it's how to downgrade using a time machine backup. So I'll really appreciate if someone can give me a hand with it! Thank you very much in advance!