VIDEO Windows 10 reverts to Win 8.1 after format

[1] First i decided to format my laptop for because of a problem i thought a virus
this video detail of problem is on description. Hope someone can help me with this

[2] Back to topic
I format my laptop using windows 10 (Settings> Update & Security> Recovery> Advanced Setup> and something in reset everything) As the Settings> Update & Security> Recovery> Reset PC is not working properly for me.

After hours of waiting i finnaly got to setup the laptop but to my surprise the problem [1] is still here and whats more is after i finish setting up laptop become windows 8.1, which is supposed not to happen as i have upgraded to windows 10 long ago and old files have been removed already.

timeline for my laptop windows is:
2014- bought it in using windows 8.1 til the release of free windows 10 upgrade (2015?)
and around the time of windows 10 upgrade i delete the old files of 8.1 and format it and goes back to win10

2017 march 22 -formatted due to problem [1] and im confident that it will be normal like i did before but it became 8.1

Question is how to fix this and how can i go back to windows 10 since free upgrade is long gone?