Hi all, I'm revisiting an old 27"iMac - a couple of years ago I did a reinstall back to the original Dvds (running Lion) thinking it would run smoother & faster etc. Realising I was heavily restricted in most basic 21st century activities in this prehistoric place I have tried in vain to upgrade to El Capitan from which it seems, I can continue to upgrade to high Sierra and beyond. I'm just having trouble actually getting to the El Capitan stage; I can't find a reliable source of this OS anywhere. Does it still exist on the web or is there a work around?? Many thanks!