On the Main PC:
Rightclick on 'My Network Places', go to properties.
Find the Internet Connection icon, rightclick, properties
go to the last tab (Sharing i believe)
Click 'Enable Internet Sharing for this connection'.
On the 2nd PC:
Rightclick on 'My Network Places', go to properties.
Find the LAN connection icon, rightclick, properties
Scroll down to 'Internet Protocol TCP/IP'
Click 'Properties'
Set the IP to 192.168.0.2
Subnet to 255.255.255.0
Default Gayway: 192.168.0.1
Preferred DNS server: 192.168.0.1
... and hopefully it'll work
