Network Connection Wizard
The easiest way to setup Windows computers to share with each other is to simply run the Network Connection Wizard. This will streamline the process of putting your computers in the same workgroup and configuring the windows firewall to allow the connection.
Go to Control Panel -> Network Connections. On the left side of the screen you should see an option to "Set up a Home or Small Office Network". Clicking on this starts the wizard. Here are step by step instructions to configure the Wizard, starting with the first screen.
1. Click "Next".
2. Click "Next" again.
3. Leave the second option selected and click "Next".
4. Enter a computer name and description of your choice. This setting may already be configured to your liking, and you can simply click "Next".
5. Likely in this place it says "HOME", "MSHOME", or "WINDOWS". Change this to something appropriate to you, that makes sense and that you can remember.
6. Leave File and Printer sharing enabled (first choice) and click "Next".
7. Click "Next" to confirm the settings.
8. Assuming both computers are running the same Operating System, you can select the option not to create a Network Setup CD and select "Finish".