You should buy it from a legit retailer such as Newegg, Amazon, etc. although why not go for Windows 10 at this point?
Best way is to buy it from Microsoft directly, which you can do by going through your updates settings on you PC or you can visit their webpage. Going with Windows 10 would be best now. All future support for operating systems prior to Windows 10 will not be receiving any support or optimization for CPUs made in summer of 2017 and later.
You should buy it from a legit retailer such as Newegg, Amazon, etc. although why not go for Windows 10 at this point?
Best way is to buy it from Microsoft directly, which you can do by going through your updates settings on you PC or you can visit their webpage. Going with Windows 10 would be best now. All future support for operating systems prior to Windows 10 will not be receiving any support or optimization for CPUs made in summer of 2017 and later.