Windows 7 Professional File Sharing
This articles gives a few tips on file sharing using Windows 7 Professional
File sharing under Windows 7 Professional is a bit different than Windows XP. Here are a few pointers:

Go to Network and Sharing Center, on your computer you want to share stuff.

Make sure your network your connected to has been classified as a Home or work network NOT public (this will disable everything with file sharing).

If that is all good, go to "Change advanced sharing settings" on the left side of the screen. Expand Home or Work, make sure

Network discovery is ON

File and Printer sharing is ON

You might want to consider the pros and cons in turning Password Protected sharing off.

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