I bought a used computer (ASUS). I bought a product key at Office Depot for Win 10 Home. The computer has Win 10 Pro which won't let me downgrade after trying to install Win 10 Home and using the product key from Office Depot. I try to download Win 10 Home but it keeps installing the Pro version. It has been useless trying to get help from Microsoft. Trying to do the right thing. Thanks in advance!