Instructions
Place your video files into a public folder on your network. This is a file that can be accessed by any device on the network.
Open Windows Media Player. Click the "Library" tab and choose "Media Sharing" from the list of options. Check the box that reads "Share my Media." Choose the device you wish to share media with from the list and click "Allow." Save the changes.
Power on your PlayStation 3. Choose "Videos" from the main menu, then choose the laptop from the list of devices. Click "Videos" from the menu followed by "Folders." Finally, choose the folder you wish to stream the videos from. Select the video, and play.