I read http://support.apple.com/kb/HT3774 and found a lot of requirements for it to work.
Bob
HI
I have a macbook that I use with my tv as a media center computer (the screen is broken so I cant use it any other way).
Im also using a windows 8 laptop and homesharing of itunes works fine...
as long as my tv is on.
When my tv is off, I suppose my macbook hibernates and I cannot access any of the music from my MacBook on my windows machine.
wake for network access is selected on the MacBook so it should work, but it wont
macbook is connected to router via ethernet cable
and my pc is via wifi

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