I have been using my PS3 as a media streamer for quite some time now. However, lately it is often having trouble recognizing the media servers (Tversity and Windows). Sometimes there is no problem and others I have to turn off my PC and then turn it back on. Turning the PS3 off and then on won't work. Also, selecting 'repair' from the network connections menu doesn't help either. Any help would be greatly appreciated.

From what you're saying it looks like there is a problem with the software/network setup on your PC. Check your firewall settings and make sure you are using the latest versions of the streaming software. Also check the physical ethernet connection. Try updating your router firmware and see if there are any settings in your router that you can modify to increase the efficiency of the streaming software.