My first computer was a VIC 20 with 4k memory! I bought the upgrade that gave me 16K.
I learn to write BASIC code (but never was any good at it).
So I have used every Windows version up to WIN 10. I am comfortable with my VISTA and it has all the software I need on it so as long as it works, there is no need to upgrade.
Wow! What did you need all that memory for?
My first one was a COSMAC Elf, with 256 BYTES of memory. (Look it up if you don't believe me...)