Please HELP. I upgraded to Windows 8.1 and now I can't even sign on to computer. [View all]

As I understand it, my signon password for my computer must now match my password for my email account associated with Microsoft. I used my laptop (which, thankfully still has Windows 7 on it) to change my email account password, but my desktop (With Windows 8.1) still doesn't recognize the password so I can't get on the computer, let alone the internet. I tried to get help from Microsoft, sending an email explaining the problem and what I did, but all I got back was gibberish. No help at all.

So I'm asking this group for help. Do I not understand the 8.1 change?

PLEASE HELP!