If you just want to share files and/or printers (i.e there is no Internet sharing involved), give the two network adapters fixed IP addresses such as:
PC1 - IP address 192.168.0.1 Subnet Mask 255.255.255.0
PC2 - IP address 192.168.0.2 Subnet Mask 255.255.255.0
The Subnet Mask is the *same* for both.
To do this, open the Network Connections folder, right click the Local Area Connection and select Properties. Highlight the entry for "Internet Protocol (TCP/IP)" and click the Properties button.
In the Properties sheet that opens, click "Use the following IP address" and enter the addresses as above. As there is no Internet involvement, leave the Default Gateway and DNS server addresses blank.