[Skybird]

Reverting back to W7 after you installed W10 is an option that MS offers, but that not for all people goes smooth and troublefree, it can give you a broken installation. Which is not surprising, considering that we talk of exchnaging ALL of the OS, not just an installed program or a data folder.

What you gonna do, you ask. Get one clean installation of W7 via your factory DVD, switch off all WUS-related stuff and THEN activate it, else WU starts maqybe while you even wait for activation. Next clean it of all the bloatware you do not want or need, and do not install anything that must be frequently updated. Make a slim, solid, trustworthy installation - and then create an image of this with an external tool, to an external HD. Keep this drive safe and declare it holy.

Not before now you start to install software, security scanners and such. If you still go with WU, do it manually - while when you do not update it at all anymore, go with another OS for all your needs, as I often explained in this thread.

Have a list with KB numbers of updates that are dangerous, and filter them out in WU, never run WU in automatic mode.

Get GWX control panel.

Do not trust words given by Microsoft, do not trust their file ratings of "optional", "recommended", "essential". They have abused them to deceive the nagware they wanted to push onto people's HDs, upgrading optional W10 advert files to recommended files, and so on.

Be on your guard, deal with MS as little as you can.

And the most important and only really reasonable advise of all: use alternatives. Everything else in the end is just a lousy compromise, leaving your system either vulnerable or corrupted. There is no really trustworthy solution under Windows anymore. Not W10. Not W7.