WMP 12 on another computer found my computer

[fritzmom]

Hello
Bought my sister-in-law a laptop, Windows 7 Home. Opened up WMP 12 to make sure that it could play CDs and DVDs without a problem. The laptop is WiFi enabled and was connected to our home's router. Under 'Other Libraries' it showed 'Barb (Barb-PC)' Barb being me. However, I could NOT access my computer or my WMP library from the laptop. My PC (windows 7 pro) is NOT WiFi enabled, but is hooked up to the router via a CABLE.
My husband's PC, also NOT WiFi enabled and hooked up to router via CABLE did not show up under 'Other
Libraries'.

I have NOT allowed 'Internet Access to Home Media' or Media Streaming with Homegroup (to be honest I don't even know what that all is).

I am very curious to know why and how this brand new laptop was able to pickup my computer. Should I be worried that a neighbor or someone else in the vicinity can access my computer?

Thanks for any input
Barb

 

[ThrashZone]

Review these,
HomeGroup from start to finish
http://windows.microsoft.com/en-US/windows7/help/homegroup-from-start-to-finish
http://www.sevenforums.com/tutorials/43972-homegroup-add-computer-join.html
File sharing essentials
http://windows.microsoft.com/en-US/windows7/File-sharing-essentials
Share files with someone
http://windows.microsoft.com/en-US/windows7/Share-files-with-someone