how to uninstall windows 8.1?

That's impossible.  You or someone else must have started it.  Windows 8.1 will never be automatically pushed to your computer unless you request it.  I'm sorry that you accidentally started it, or that someone used your computer without your permission.

You can remove it using the steps that VanCountry politely provided above.  However you are misinformed:  Windows 8.1 has no such requirement to use a Microsoft Account.  You can continue using it without that and without a password just like always, because nothing changed.

Just click "Sign In Without a Microsoft Account" at the bottom of the page:

I Had sky.com as my default homepage before I upgraded to windows 8.1 since then Ask.com is now my homepage and I cannot remove it as it is not in my programmes

Since I installed Windows 8.1 I have several issues and problems.  I want to UNINSTALL 8.1.  How do I do it.

Since I updated to 8.1 I seem to have a new issue everyday and I can't seem to resolve any of them.  Windows Media Player will not work and now a lot of the start screen apps will no longer work. 

In addition to the above issues, occasionally parts of my screen go black when I am scrolling down the page.  If I click on the page, the missing parts will come back a little at a time.

I need to resolve the media player issue as I need it for my job.  I have tried the recovery option explained in this thread, but that did not work either.

Windows 8 was great and I didn't have any problems.  I really would like to get it back.

Thank you to anyone who has an answer.

Ever since 8.1 was downloaded, I have not been able to properly use my work email.  It has also deleted printer drivers which were a handful to do in the first place. I really, really, really need to uninstall this.  Please tell me how I am able to go about this.  Thank you.