You can get your key in a number of ways, my favourite is to enter the following at a command line:
wmic path softwarelicensingservice get OA3xOriginalProductKey
It’s a good idea to save your key as soon as possible just in case. However, when asked for the key during Windows installation do not enter one! The BIOS key should be detected later on.
Before doing anything I would use a disk imaging package to save the current state of the tablet (my preference is Macrium Reflect).
I believe you have the correct version of windows, but you can double check by right clicking on the “start button” and going to System. You don’t want to even attempt booting an installation USB with the wrong version of Windows on it.
Manual installation of drivers can cause issues, sometimes not everything gets installed. If possible use individual installation packages for just the devices that Windows doesn’t manage to sort out itself.
By the way, you probably won’t achieve much in terms of performance by doing this, it seems from the review on this site that the Plus is slow but with a long battery life.
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