A tech manager at the office gave me a unused, sealed My Passport 1 TB external HD that is a few years old (WDBBEP0010BBL-NESN.) I use Windows 7 on one laptop and Windows 8.1 on another, but will probably go to Win 10 in the next few months. Will this somewhat older drive work satisfactorily with 7, 8.1 and 10?
Yes. It should work just fine.