This is what you have to do to connect an Xbox360 to Xbox Live through
a 32bit Vista computer:
1. Plug in an internet cable between the computer and the Xbox, and
make sure the Xbox is turned on.
2. Create a bridge between the wireless network and the local network
- Go to: Network Connections
- Mark BOTH the Local Network and the Wireless Networks you want to
make a bridge between.
- Right click, and choose "Create bridge between connections"
Now the Xbox360 should be connected to Xbox Live.
I might be mistaken, but it seems your problem is that you haven't
chosen both of the connections you need to make a bridge.
Hope this helps