What hardware did you upgrade? Did you install all necessary drivers for Windows 10?
And did you already find the Windows 7 drivers for your upgraded hardware. Otherwise it's quite well possible you don't have sound there either.
Removing all partitions from the HDD with your favorite partiotion manager suffices to install Windows 7.. No need at all to throw it in the bin.
I got caught with win 10 and came home and found it loading ok so I ran with it and it was good but slow for a couple of months, then my processor died and I did the upgrade to the hardware And now I have spent a week trying to find out why I have no sound or shut down
So I looked at my win 7 disc and thought stuff this rubbish I,m outa here. Im going back to 7 at least there is no probs with that and you can find stuff, without a tool to decipher all the stupid new terms in 10
Then after searching the forums it seems the only way to get rid of it is throw the HDD in the bin,

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