The simplest form of connection between two computers is a direct connection, using a single Ethernet cable to enable data transfer. You must install networking cards on each computer if they do not currently have an onboard Ethernet port or a networking card installed. A networking card plugs into one of the PCI slots in the computer's expansion area and contains an Ethernet port.
Plug one end of the Ethernet cable into the Ethernet port on the first computer. Make sure you insert the Ethernet cable's connector into the port completely; you should hear a click when the connector's retaining clip slides into place.
Plug the other end of the Ethernet cable into the Ethernet port on the other computer. Make sure you insert the cable's connector until you hear the retaining clip snap into place.
Boot up both computers.
Click the Start button on the Windows 7 desktop, and click "Control Panel."
Type "network" in the search box. Click "Network and Sharing Center."
Double-click the Unidentified Network icon at the top of Network and Sharing Center.
Click "Turn on network discovery and file sharing" under Network.
Provide confirmation if prompted.
Things You'll Need
Category 5 or better Crossover Ethernet Cable
If you're installing a new networking card into either computer, select a card that provides a fast transfer rate. Networking cards are rated 10, 10/100 and 10/100/1000. This refers to how much information they can transfer per second. Available speeds are 10 megabits per second, 100 megabits per second, and 1 gigabit per second.
You may need a different kind of crossover cable to take advantage of Gigabit Ethernet. Ask when you purchase the cable or contact the cable's manufacturer for help.