Just so those who are experiencing the problem dont think they are going mad and imagining things, I have the same network problems on this build.
I have since deleted and gone back to a pre christmas build and I have my network back.
I can rule out any issues with the pc or simply restarting the network, there is definetly a problem in there somewhere. I will give brief details incase it starts any thoughts, I only have a simple setup, Xbox linked directly to PC with an ethernet cable, anyways.
So, I can confirm my sources dont work, ie I have my shared folders as a source in music and videos accordingly, the address is something along the lines of "smb:\\HomeNetwork\HomePC\Media Drive\Music library\". These no longer work.
Manually connecting to my network using the default Workgroup SMB shortcut and then browsing from there wont work either.
Like I say, not much else I can throw up really, just thought id back up some previous posts. Incidentally, I am still running RSS feeds and can access t'internet from the box.
My box is pretty much redundant unless I can stream so I am stuck with no updates and no nice pretty wide icons until this is fixed! boooo!