Can't get acccess of video and mp3 files folder in Windows 7 Laptop

[zhong]

I can't get acccess of video and mp3 files folder in Windows 7 Laptop.
So I can't stream anything from my laptop.

On Mag 254-
When I go to "Browse Media" section and go into LAN I am able to get in my Windows xp computer(s) folders without need for authentication (username and password).

But when I try to get into my Laptop asus computer. It asks for authentication,
What username and password do I use to get in ?
I don't use any username and password to open Windows on my laptop. It just loads straight to desktop after I open it.

Thanks


Zhong