Connecting to wireless G, but no internet

This is my network

1. Dell P2 XPS desktop
2. Dell 2400 desktop
3. Dell 710m laptop
4. Dell Inspiron 5100 laptop
5. Dell XPS M1330 laptop
6. MacBook

I am running the P2 XPS(#1) hardwired to the Netgear wireless N router. I have a Netgear Powerline Extender that is wireless G.

This is my situation.
Everything can connect to the wireless G Extender, except the new XPS M1330 connects, but gets no internet. However, the XPS M1330 can connect to the wireless N router and get internet.

So, the 1330 can only connect to the N, but not to wireless G. All the other computers can connect to both. What’s going on?

Please help. Thanks in advance.