I followed the instructions on this page to make sure my account is an administrator account:
http://www.windowscentral.com/how-change-user-account-type-windows-10
Then I logged out of windows 10 and back in to as requested to finalise setting the account to administrator.
And I redownloaded 'Nesplayer SM64 hud Up.zip', and the same thing happened
The strange thing is that the zip file will extract fine normally when on a folder on the desktop. As soon as I put it in C:/Program Files (x86)/Project64 2.2 (or anywhere on C:/), though, it firsts asks me for permission to transfer 'Nesplayer SM64 hud Up.zip' to that location (which I accept) and from then on won't unzip.
I tried running 7zip from the exe and it in the folder structure it showed 'program files' but not 'Program Files (x86)' which maybe the problem as 7zip doesn't seem to recognise that location.
Would the answer be to unzip the 'Nesplayer SM64 hud Up.zip' file on a folder on the desktop and then manually transfer the relevant folders/files to the 'C:/Program Files (x86)/Project64 2.2' folder? If so, can I as where to put those files/folders?