See
Project Cartographer mod is inbuilt into xlive.dll present in your Halo 2 Folder (C:\Program Files (x86)\Microsoft Games\Halo 2)
Just rename it to something else or just delete it temporarily to Disable the Mod
After that u can Do what i said above
If u havent manually added the -nosound parameter then i can certainly say its not related to launch parameter
Nevertheless do try to launch the game directly from the Halo 2 folder itself
Cant say for certain what might be causing this
Does this problem happen with your other games as well?
If...
Currently Project cartographer doesnt support LAN local multiplayer mode which it will in future hopes
But u can still play Halo 2 on Lan
For that u gotta remove the project mod (just remove the xlive.dll frok your Halo 2 folder)
That should bring back the Windows Live
So Create Offline profiles...
Its best that you install and play it from same location itself
Its not that launching from other places than install directory wont work but it might cause issues with account system and the Update system
Right now we havent put up tutorial for hosting dedicated servers because the network browser is pretty much unstable right now ,the more the servers increase the more it flickers
Hosting dedicated servers would be made public when we overcome this issue
Sry for now all u can do is host custom...
With due regard coop mod is pretty much broken and incomplete and i would rather not suggest trying it.
With the current state it in ,its not much enjoyeable and is full of desync
So i would suggest playing coop only when its officially released in project carto future updates
In Case of Custom hosted Games its Party leader is the host
In case of Dedicated Servers(with CPU icon) ,theres nothing which decides the host,its just neutral for all
His pc is so powerful and still ..
Could be monitor issue or the powerplan check this
http://www.tomshardware.com/forum/id-2999517/monitor-disconnects-randomly.html