Since a recent upgrade to Windows, I can’t get my hotmail account to work. I didn’t change any passwords, but it won’t receive or send e-mails to my POP account STMP server. Help?

I own an IMac desktop, an I-phone and an I-pad.  I use all three interchangeably.  Since a recent upgrade to my IMac, and a change to IOS7, I can't send or receive hotmail on  any of them.  I didn't change any passwords or settings in hotmail, but it won't work.  My gmail account works well.