One computer receives mail from recipient, other computer does not receive same message from same recipient on Windows Live.

I don't know what is going on.  I must have done something to cause my HP windows 7 computer to not receive the same message that is sent on my HP Vista.  It is from my daughter who I receive her emails on Windows Live Mail, but then when I look at the Windows Live mail on my Windows 7, the message is not there.  I click on send/receive at the top of the page, but the connecting small window just flashes really quick, and disappears.  On my computer that I receive her messages on the window from send/receive option, shows connecting and displays new message.  I don't know what I clicked to make this start happening in the last week.  As far as I know, this just started. 

I also noticed that I can send a message on my Windows 7 computer to her and she receives it.  I always check "send" to make sure it was sent, which it is.  But then when I go to my Vista computer that I receive her emails on, when I check the "send" to see if it is posted, it is not there.  I have contacted my internet service, and my pop.mail and addresses are correct in "properties" under all the headings.  I also made sure my contact list on her address is correct.  Identical on both computers. Beats me.  I am so baffled.  Please help.  How will I find out if anyone can answer my question?