Confusion on Microsoft Passwords

I really do not know how Microsoft stays so popular...they are the most frustrating company, program, OS, I can imagine ever existed!  Yesterday I needed to change the password due to my son being on my computer when I got home.  When I changed the password I received a warning that I may need to also changed linked passwords to other accounts.  I followed some "links" and changed the password in my live.account - however, when I was in my live it told me I could not use a password that I have already used (it was the password I just changed it to, and I was assuming they wanted me to change them all to the same password so I wouldn't get blocked or something - not to mention, I have too many passwords for too many sites that this is practical) in doing all this.  So I thought my Windows logon and my live.com login had two different passwords...seemed to have worked for a while - except I'd get this message that my Windows logon was offline and I needed to enter the last password used - I figured this meant my very last password I used anywhere - some sort of security "smartness" - luckily this worked!  Later come to find out that the password I had to change in live.com is now the password for my Windows logon - this is so confusing and I don't understand what's what with Microsoft...there are too many "connections" with Microsoft to be linking passwords like this...hate to see it later when I log on to my son's Xbox, thank goodness I don't do that too often!