PS3 > laptop probs

[telboy]

Hi all, Maybe someone on here can help me with my dilema/problem.

While I play on the PS3, the missus usually plays games on the laptop.

All of a sudden, I can't have one on without the other not working. If she's on the laptop and I switch the PS3 on, it wont let me sign into PSNetwork to get online. If I'm on the PS3 and she puts the laptop on, it won't let her play on her games. Sometimes it won't let us do either.

It comes up on the laptop with 'there is an IP conflict with another system on the network'.
It's never done this before, only recently.

Any ideas on how to cure it and stop it from happening?