PC stuff (2)

Next PC runs dual OS. 

(1) One is Windows 7 (64 bit).  Another is Linux.  So needs more RAM:  8+ GB. 

Can files saved by Linux be accessed and read by Win7?

3 Ways to Access Your Linux Partitions From Windows (mirror) by Chris Hoffman on June 7th, 2017

A Comprehensive Guide to Sharing Your Data Across Multi-Booting Windows, Mac, and Linux PCs  2010 - old?

(2) One is Windows 7 (64 bit).  Another is again Windows 7 (64 bit).

(3) One is Windows 7 (64 bit).  Another is Windows 10 (64 bit).  Where to get Win10?