If your router is hacked as suggested in a sister thread then possibly it is has managed to modify a download to get a virus on your computer like the CryptoLocker.
However, could be a copy of Netflix and your router deliberately set to access this clone whenever you visit netflix.com
You might want to check if the IP address of netflix.com changed within your home environment. If it has, go to a neighbour, and either change your password if still possible or call Netflix Support because they could have hijacked your session cookie already -- which basically means "free Netflix account" (for them). Also don't visit other sites (until you get a new router) because they might be rerouted aswell.
This is why I only use routers that support OpenWrt.
It might not even be your neighbor. Could be a virus she has or something. I'd ask your neighbors though, if you think any look like the type that would do this.
The netflix app was showing you porn?