This process will make the network a little less secure but it works well because a password isn’t used and everyone is allowed access.
First, know what the Computer name is and what Workgroup it belongs to. The Workgroup name needs to be the same on all PC’s that are being networked no matter the OS on each system. This is already setup, even if only by default, in the setup process while installing each OS. Verify what the Windows 7 computer and workgroup names are by going to Control Panel System and Security System and read information under “Computer name, domain, and workgroup settings” (The third category down).
If the names need to be changed go to Change settings in that category or Advanced System Settings in left pane. Then, Computer Name Tab > Change, type the Computer Name and Workgroup Name. OK, Make the computer name meaningful to aid recognition. The computer should restart.
Second, adjust Win7 settings to allow for sharing with older OS on other networked systems by going to Control Panel and in the search box type "Network". Then select Network and Sharing Center. Next pick Change Advanced Sharing Settings (side panel). Make sure Network Discovery, File and Printer Sharing, and Public Folder Sharing are all set to “on” and Password Protected Sharing is set to “off”.
Note: I recommend leaving Media sharing set to “on” and under Windows HomeGroup connections select “Allow Windows HomeGroup to manage homegroup connections (recommended)”.
Next decide which folders you wish to share on the network and do the following:
Open up the properties screen on the folder you want to share and control tab once.
Hit the space bar on the share button.
At that point a list will pop up, simply down arrow to everyone.
Then tab four times, and hit the space bar on the close button.
On the screen that will pop up shift tab twice to the done button and hit the space bar.
Next control tab to the security tab.
Tab to the edit button and hit the space bar.
Tab to the add button and space bar on it.
Then type everyone and enter on the OK button.
tab twice to allow full control and space bar on it
Verify the settings by tabbing across the various check boxes.
Hit the Apply button and then the OK button.
shift tab to the close button and space bar on it