A few questions about installing Win10.

[panirwane]

I've got a few questions about installing Win10.

Context

1. I have a windows 7 PRO key and a windows 8.1 pro key (via my MSDN subscription).
2. I have windows 7 w/SP1 x64 iso, an 8.1 iso and a new windows 10 pro x64 iso.

1st computer questions.

1. I have a machine with a formated HD (nothing on it). To install windows 10 on it, do i need to install windows 7 (and do nothing else .. eg. no windows updates, etc). activate win 7. THEN install windows 10 over that?
2. Can i just install windows 10 onto a freshly formatted HD and provide my windows 7 key/windows 8.1 key as proof that I have that/them?

2nd computer questions:
Context
For my my work machine, it's OSX with Parallels+win 8.1 pro. It's bootcamped so i can bootcamp over to win 8.1 native for when I play games. When i'm in win8.1 natively/bootcamped, it's activated. When i'm in parallels, it keeps fraking with me saying i'm not activated every 2 hours or so. urgh!.

Q3. If I upgrade my 8.1 pro to win 10 when i'm in native/bootcamp mode, will parallels keep fraking with me saying i'm not activated?
Q4. where should I do the windows 10 update? in parallels or bootcamp? Will I always get hassled in one of the two modes? is it possible to tell Microsoft activation that i've got my keys and I'm trying to do the right thing.

thank you kindly for any help - really appreciate it!