Problem with Home Networking

I have a Toshiba notebook with XP Home installed & a desktop with XP Prof. installed. The desktop is connected to the net through a DSL connection and acts as a gateway for the laptop. The laptop connects to the the desktop through a hub.

This setup used to work fine till a few days back. Suddenly it stopped working, i didnt make any changes. Now i cannot connect to the net from the laptop, but i can see both the computers on the LAN and even share files. Net works fine from the desktop.

The IP address is assigned automatically in the laptop & the gateway is set as 192.168.0.1 (which is the local ip address of the desktop). Please help me get net back on the laptop !!