You might want to try to make sure that you have saved the media you want to stream to the Windows7 shared or public folder. If you have created folders within the shared folder, you might have to turn on the file sharing within those folders as well.
Here's a link for the homegroups tutorial from Windows' side:
I never had issues with PC Streaming onto the BD1250 when i had XP.
Now i have Windows 7 it askes for user name and passwords, and also claims there is no shared folder.
I have tried all combination of user names and passwords, including nothing. I have messed around with the sharing settings but it still is not seeing any of my files.
I thought that the homegroup was supposed to make these things easier?
I have already done all the updates available on both PC and Blu-ray.
Thank you very much!