WIN 7 & XBOX 360 Network Discovery

I have been struggling to get my WIN 7(64) Ultimate to work with my XBOX. It won;t even see the XBOX on the network with WMP (streamin to Local Network is on), ZUNE, or Media centre. I can ping it and they both connect to the internet without difficulty.

I have it working fine with the 32 Bit Ultimate Eval version that I still have on my Laptop. From what I can see the setup is the same. (no difference in network configuration either) I can also share files between PC/Laptop without any issues.

Am I missing something, I have disabled all Firewalls/AV. Checked services etc

I'm an Information/Communications Systems Engineer and I know my stuff but this one is really getting the better of me. Any help would be appreciated!

Well Matty I just finished installing Media Center into my new Dell XPS 9000 Windows 7 64 bit (wired) and my son's XBox 360 (wireless connected). I didn't have a single hitch. Everything worked fine. I started with the XBox 360. I went into the Media Center configuration section of the XBox menus and continued setting up the XBox until it came to the part that said "Write this code down and install it in your computer". I must stop here for a second and mention that the Media Center configuration program on the XBox 360 complained that the XBox wasn't getting an IP address through DHCP (I assign fixed IP addresses to all components on the network) but I just ignored the warnings and it worked anyway.
After writing down the code I went upstairs to the computer and ran the Media Center Installation Program. During that installation process on the computer it asked for the code from that was displayed from the XBox 360. I just entered the code and continued with the installation. The installation on the computer did get a little hard to follow when they started talking about adding libraries and such.
I ended up just adding a photo library from the computer of our European vacation. I'll add other libraries later (videos, music, etc). I then went back downstairs and watched our vacation pictures (which are stored on the upstairs computer) on the TV (which is downstairs and hooked to the XBox).
Do these setup steps sound like what you did?
Please let me know if this helped you out. I'll check back later for a reply.

Thanks DaLog but I wasn't that interested in the Media Centre side of life, I only went down that road as an alternative means of getting some comms between the PC and XBOX.

In the end I did the following:

Returned everything to standard
Removed both PC & Laptop from the Homegroup (originally PC joined the Laptops Homegroup)
Restarted them both and turned off the XBOX 360
Created a new Homegroup on the PC, joined the Laptop, made sure media streaming had been turned on and file sharing was okay.
Powered on the XBOX and it was detected in WMP and ZUNE (didn't check Media Centre but i'm more than confident it will work)
Shared all required libraries to the Homegroup

No explanation of the errors or cause of the problem, the only difference in the setup this time to when I first did it was I created a new homegroup on the PC instead of using the one previously created on the laptop (even though the share settings were identical this time round)

Put it down to Microsoft, I refuse to accept that it was anything I did ;-)

Matty I must admit that I am somewhat confused. If you weren't interested in getting the Media Centre to work, then exactly what was your ultimate goal? When you said that you were interested in getting comms between the PC and XBox, what were you TRYING to do? Were you trying to get the XBox to access the network so you could play multi-player online games?
Where you trying to access photos, videos, music stored on the Win 7 (64) desktop and display them through the XBox onto a TV?
The reason I am asking these questions, even though you have solved your problem and don't need any more help, is because that you may be aware of some other functionality between PC's and the XBox that I am unaware of. Thanks for the info.

I wanted to just share files from PC to Xbox (so i can access HD videos etc and watch them on my TV, or play my music through my surround sound system) using WMP or Zune, I'm not really a fan of Media Centre. The problem was I couldn't even see the XBOX on the network. Before Windows 7, WMP 11 set up xbox media sharing, and it hasn't really changed. WMP is still used but the method is slightly different.

OK I understand what you were trying to do now. Thanks