Hmmmmm
I have a 6200, no problems with 704 atleast.
(you are using 704? not one of the betas?)

I was (am) a windows guy as well, you should quickly find your way around.

Your problem is very common, weird you didn't find it on a search. Anyway.
Delete the MD you made in the admin, does it really say in the Wiki you need to add it manually?

The procedure is simpler (and unless you start using GF 7xxx or 8xxx until 710 is released it should work great).
The core needs to be on (DHCP server)
You need to connect the MD to the internal network (are you using a single NIC?)
You need to power on your MD (set to PXE/LAN boot in the Bios)
You might get a message at the core that it's found an MD, but it should work regardless.
Now sit back and relax, the core will add the MD and install it (on the core) making the MD a thin client.
Setting up the MD can take some time depending on CPU/RAM on both MD and core and also the network (My worst was when I used a 1.7GHz core, that took 7-8 hours), remember you are doing a full install of the LMCE client, on the core, for every MD.

GF8400 it would appear
http://forum.linuxmce.org/index.php?topic=3975.30

I did believe drivers for that chipset/card would be in the 710 release.
Another question is ofcourse, what do you use to display the computer image?
(A monitor would be the safest bet until you know it works/you know it better)

Your a real piece of work Zaerc.  There is no use for trolls here.   

You are absolutely correct, there is no use for trolls here.

Did you think that's possible to put it a small linux distrib to make a md ?

No, not at the moment.
LMCE 0704 is tied to Kubuntu 0704
LMCE 0710 (beta3) is tied to Kubuntu 0710
It wount work on other distributions yet. (There are examples of installation on other distributions, but that takes a lot of work)

I have had that error once, but it was due to faulty RAM.

Hi guys, as we all know (we do, honest, deep down) that one reason for having a computer in the living room is to play on it.
Could this technology be adapted to display (and control) a windows game from a LMCE MD?
http://streammygame.com/smg/index.php
That would be "supercool" GoW for PC here I come

Do you use LMCE to rip the movies? it sounds like you are using some other program.
LMCE makes isos (.dvd)

eh...
Ok, what version are you trying to install?
And on what version of Kubuntu?

There is only 32bit versions of LMCE available to the public (until the release of a 64bit beta), both 0704 and the 0710 beta is 32 bit, and can only be installed on Kubuntu 32bit (0704 or 0710).

Kubuntu 0704 32bit should work on the AMD64

0710 will have native support for AMD64bit, but 704 should still work on it.
Have you installed the 64bit Kubuntu? that could be your issue.
LMCE 0704 will only install on the 32bit Kubuntu 0704 (I386)
(if you wait a bit for 0710 you can install it on Kubuntu 0710 64bit)

(I have problems, and it's in the mantis as an acknowledged problem )
But I can also get it to work flawlessly, I feel the remote is very good and perhaps even more important to me than the UI.

A long time user of XBMC, I decided it was time for a more powerful media center.  I picket up a media pc case for free from a friend and started looking around at various media centers. 

Good for you

I first tried mythtv on debian etch.  The install went fine.  I had to do some tweaking to get X and nvidia working together nicely, which went fine.  I want a single interface that my girlfriend is capable of using for music and movies (like XBMC), but mythvideo and mythmusic weren't that great. 

Sounds like you really just want a media portal (http://www.team-mediaportal.com)

After some googling, I decided to give this LinuxMCE a try.  I downloaded the DVD after verifying the md5sum, and I watched the demo video.  I must say, what a scam.  There is no way that is "just works" without knowing how to modify your xorg.conf and alsa setup, unlike what is preached on the home page.  I had to kill the X server (ctrl+alt+backslash) and debug the issues causing X to run incorrectly and my TV to show "unsupported mode."  It turns out that disabling the EDID is a bad thing in xorg.conf for my nvidia card.

I didn't have any of those problems on any of the five PCs I have tried so far.

Anyway, after that fiasco, the graphics kept disappearing while "Sarah" was talking during the initial setup.  I ran the AV setup again this time at 640x480 which kept the graphics on the screen, but afterward, I see that for some reason it's running its own dhcp server in stead of getting an address from the one I'm already running.

The DHCP (as has allready been mentioned) is a key part for LMCE, and also the reason (in my opinion) why it isn't really suited for a single mediaportal installation (did I mention mediaportal above...)

There is no option in the UI to change that, and since I don't feel like fixing it manually, since that is just going to be one of many more problems I'm sure (from the way things have gone so far) I am going to have to fix, I'm just going to scrap it for now. 

That's what the webadmin tool is for, you can't expect all the small details to be on the 10' interface on a system this complex?
Remember this is intended as a media-server/file-server/router/controller/firewall+++
And you usually don't set the options in your firewall on your TV either?

Again, that demo video is a joke.  There's no way a Linux novice could get this working.

Not a joke, it worked for me when I followed the instructions, and I hadn't touched Linux before either.

I have the XP version, I do believe they are virtually identical, the only real difference I can see is that I can't detach the USB on the back of the IR blaster/receiver.
I have had some trouble getting mine to work along with my GF7200 card.
But I have had mine working flawlessly with internal video and UI1, so it could be just a fluke or my hardware setup.
It is detected automatically and installs something called 'lirt' (I'm no guru).
But it's a 50/50 chance as ddamron says. (could be a conflict with the the older nvidia driver that really does not support the 7200... I don't know)

As mentioned, enough Cat6 cables, or Cat5E (the E is important).
Make sure they put in enough conduits so that you can pull additional cables later.
Also if you plan a home theater make sure they pull conduits for a 7.1 surround, even though you do not have it now, crawling inside walls is not very easy (unless your an inch tall).
Also have all the cables for phone and ethernet terminate at one spot/cabinet, a few years ago they would just pull one cable and hook all the phones up in parallel, this will not work particularly well for a good computer network. (I am struggling with such an installation, and pulling the four cables necessary to get the same coverage trough the existing conduit is not possible).

You're not alone