Currently Being ModeratedNov 26, 2012 1:25 PM (in response to CorkLad910)
Yes you need your computer on if you want to stream from its library, even if the library is on an external or network drive.
However any purchases you have made from iTunes can be stream from the iTunes Store at any time without your computer being on.
Currently Being ModeratedDec 7, 2012 10:22 PM (in response to CorkLad910)
Be warmed, Apple TV is having issues staying connected to your network! For the past three weeks our 2012 Apple TV craps out after a few minutes. We bought a time capsule at the same time. Haven't had any issues for about 6 months, maybe it's the new OS. Very frustrated and disappointed in this Apple product!