Reinstall W10 or 'Custom'?

[Mac291]

I'm installing W10 (Pro 64b) but have the W10 HDD from old system in my new build. Thinking I'd get option to overwrite (I have a backup). I think a "fresh install" is best, but it's asking if I want to 'Upgrade' or 'Custom' install. Says Upgrade will copy my files, appls, etc.

It would be nice to just switch the key and anything w/ recognizes the new hardware. It can't act like an "Upgrade install" from W7 or W8. Only Windows on this HDD has been 10. New mobo, cpu and ram. If it overwrites W10 files it sounds like same files written as during a fresh install.

What are any downsides to choosing 'Upgrade'? Also, do you think I'll get to choose between build 1903 and 1909, released today?


Thanks for any input,

Mac

 

[MaikuTech]

Your best option is to back up any data you need from your old drive.
Next you do a full format through windows installation.
Since your parts are much newer, windows current build shouldn't have much of a problem.

(with my current kaby lake system I barely have any problems with windows updates)

Also use your current windows product key as is
If your product key started off as windows 7 pro, then to windows 8 pro through a upgrade option and finally windows 10...

Microsoft activation servers will recognize the key.
If it gives you problems, call MS and calmly explain what the problem is to them.