You are using 32Bit so you cannot ADD 4Gb RAM, only 2Gb (MAXIMUM is 4Gb on 32bit Windows OS)
Genuine Windows licenses don’t expire.
The free upgrade to Windows 10 ended July 29, 2016
When you buy a new license, make sure it’s Windows 10. There is no point in considering W8.1
Absolutely, I’ve mentioned a number of times that you should prepare your assets before adding them to a video editing project. I recall one person considering my advice as some form of insanity