Really need help! :/

I have iPhone 4, iPad 4 and Apple TV, all on the same Orange livebox router, all working independently, but non of my devices will access my iTunes library on my PC. They find it sometimes, but say unable to connect 😟 They all have the same login, there is no firewall and I have disabled teh IPv6 thing. At teh end of my tether, so any help really appreciated...