The program should run on Windows 10 -- if nothing else, in compatibility mode.
It's just not going to take advantage of much of Windows 10's advanced architecture, including the ability to use more than 3 gigs of RAM.
Also, version 4 was designed pretty much to work with tape-based digital video -- miniDV and HDV tape. So if you're trying to edit AVCHD or video from phones, Go Pros or any source other than miniDV or HDV, it's not going to do a very good job of it.
Thank you for taking a moment to answer my question. I will try the compatibility mode. I am using video from a Sony Handycam.
If it's a Sony that shoots in Digital8, miniDV and HDV tape-based, it should work fine.
If you're shooting VHS, 8mm or Hi8, not so much.