Setting up two computers so they can share information back and forth is a common home networking project and one that most computer owners running Windows XP or better can do successfully without the need for "expert" assistance. Make sure both computers have functioning ethernet adaptors and are connected to your network before you begin.
Start with your home desktop computer. Turn off your firewall program. Go to "Start," "Control Panel," and "Windows Firewall" and turn the settings to off, temporarily. Ignore any warnings about this temporary shut-off.
Go to "Control Panel," and "Network Setup Wizard." Click "Next" and then "Next" again through the first two screens. Choose "Yes" to share the existing connection to the Internet (your home DSL modem or router) or "No" if you want to connect some other way. "Yes" is the default and most common choice. Click "Next."
Describe your computer (i.e. "home office computer") and name it (i.e. "Jay's Desktop") choosing names and descriptions that will make it easy for you to spot this particular computer on any list of networked computers for your home. Click "Next."
Name your home "workgroup" name. "MSHOME" is the default but it is better to name your own group. Choose and enter a name like "YourName Group." Click "Next."
Turn on "File and Printer Sharing." This will make it possible for other computers within your YourName Group to see and use files on this desktop and vice versa. Any printer attached to another computer, or this one, will be accessible to all the computers on the network as well. Click "Next."
Click "Next" after reading the settings that will be applied. You need not worry too much about these settings.
Click "Finish" and then reboot your computer. Do not restore the Firewall just yet. Go to "My Network Places" and open this folder. You should see your newly named computer in this list.
Move to the laptop or other computers you want to add to your home network. Go through this same process, being sure to reboot the machine at the end of the Wizard steps.
Open "My Network Places." Now you should see all the computers that are part of your network. If you don't see the expected results, check to make sure the other computer in the network is booted up and on line, and the firewall is still turned off. Turn off any antivirus programs, temporarily, if necessary to allow the network settings to connect.
Add files to your "Shared Documents" folder on the desktop computer and the laptop. Only these files can be shared back and forth. Files not located in the "Shared Documents" folder cannot be seen while using the other computer.
Restore your firewall once this process is complete.
Networking computers through "virtual private networks" is also possible and much easier now thanks to programs like LogMeIn.com and GoToMyPC.com. Both programs (paid for or subscription based) will allow you to log into another computer and use it as if you were physically present in front of the computer.