Actually, what I wanted to ask is whether anybody knows where I can get older versions of OSX. I recently upgraded to OS Sierra (v. 10.12.3, if it matters) and it has been a major PITA ever since (computer itself is around 7 years old). It now runs incredibly slowly; if I have to reboot I might as well go out for supper while I'm waiting for it to come back up. And even once it's rebooted, when I try to get Google to launch ... I might as well go back to the restaurant for a nice dessert and coffee. 
I'm assuming the new OS is the problem. Or is my little Mac mini just nearing the end of its life? Should I be saving up (possibly very very quickly) for a replacement?

I'm assuming the new OS is the problem. Or is my little Mac mini just nearing the end of its life? Should I be saving up (possibly very very quickly) for a replacement?
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