Extender Config Error

[nhorton79]

Sorry if this is in the wrong place.....

Oh well, here goes:
I am currently having some issues with Xbox 360 and Media Center.
Everytime I try to set up the 360 as an extender it comes up with the Configuration Error.
Here is a bit of a breakdown:
I am able to see the 360 on my computer and I have recently reset my DRM (in media player)which allowed me to see my computer from the xbox.
I have run through the suggestions provided on most forums:
1/ I have tried connecting by bypassing the router (direct connection - pc to 360) NO JOY!
2/ Have confirmed no secondary MAC address. NO JOY!
3/ Have tried to enable Filter Multicast on my router, but cannot find this, have looked through all the guides etc. and they mentioned IGMP Proxy and said to enable - so I enabled. Just to clarify - I have a DLink DSL-G604T modem running firmware version V3.00B02.NZ.20060711
4/ Have tried the suggestion of deleting the Xbox 360 Dashboard on the 360 under Memory>Hard Drive>Games. Unfortunately I can't see this file there and so wasn't able to delete it.
5/ Not on a domain.

I have checked under event viewer immediately after the error and I see:
Type: Information
Source: Mcx2Prov
Event ID: 501
Event Info: Design started Windows Media Center Extender setup with the following options: Firewall settings (0,0,1,1) Power management (0) Media settings (1)
then:
Type: Error
Source: Media Center Guide
Event ID: 0
Event Info: ERROR: SqmApiWrapper.TimerRecord failed; Win32 GetLastError returned 10000105
Process: DefaultDomain
Object Name: Media Center Guide
then:
Type: Error
Source: Mcx2Dvcs
Event ID: 401
Event Info: Windows Media Center Extender setup cannot configure the Windows Media Center PC for use with the Extender. Error code: -114.
Now I figured that this would be it and when I clicked for more info online it took me to the microsoft website where it told me that the 114 error was due to a corrupt certificate. This showed me how to find the certificate using mmc (add/remove snapin) and delete it. Unfortunately, I didn;t have a certificate so I was unable to delete it.
I have tried setting up using my friends 360 and this dfoesn't work either, so imagine it might be a Vista problem.
Please, please, please someone help me before I go insane.