How to connect two computers without a router

There are two options to connect two computer– you can either buy a router or, if you are looking for something more simple and don’t want to spend money on new networking hardware, you can connect the two computers using a commonly-available cable. The latter method doesn’t involve any complicated network settings and you will still be able to share files, internet connection, and even printers between computers.

Connect Computers with an Ethernet Crossover Cable

Before connecting the two computers with a physical cable, make sure that both machine are using the same workgroup*. Here is step-by-step guide that explains how you can change the workgroup of your computers.
Changing workgroup in Windows XP – From the Start menu, right-click “My Computer.” Select Properties in the drop-down menu, and then select the second tab that says “Computer Name” from the System Properties window. Now click the “Change…” button, enter a unique Workgroup name and reboot your computer.
Changing workgroup in Windows 7 or Vista – Open the Control Panel, type “Workgroup” in the search box, and select the entry that says “Change Workgroup Name.” Click the “Change…” button, enter a Workgroup name and restart the computer. Windows 7 users can skip one step; simply type “Workgroup” in the search box in the start menu, and select the first entry.
Now that the workgroups are same for both computers, connect the two computers together using the Ethernet crossover cable. Simply plug-in one end of the crossover cable into the network adapter of Computer A and connect the other end of the cable to the network adapter of Computer B.
Windows will automatically recognize the new network, and you can now easily view files and folder that the other computer has shared. Simply open Networks from the Start Menu (or the Control Panel), and you should see the other computer by its name. You can then browse any shared files on the other computer, and can even utilize shared printers.
Troubleshooting – If you do not see the other computer under Networks, you probably have a prompt at the top of your Network window saying that Network discovery is turned off (screenshots below). Select “Turn on Network Discovery and File Sharing.”  In the next prompt, select “No, make the network I am connected to a private network.”  Now you should see the other computer on the home network.
While it is possible to share files between two computers connected with a crossover cable without making them part of the same workgroup, the method will only work if both computers have this network set as a private network, and may still cause problems. It is therefore advisable to have both computers on the same workgroup before sharing files and printers. Now you are ready to share data between computers.