To be honest I have a 2 year old Dell desktop with windows 10. Have had no issues. I always have McAfee on. Use a portable hard drive plugged in always and save everything of value onto that. I don’t use the cloud.
Move your Win 7 drive to an external box, install all the necessary software on the Win 10 box. That will give you the file access while running on the new box.
Do you also have those files of value somewhere else? On the PC AND the external drive?
If the external dies and that's the only copy then you have no backup. Just trying to be of help.