Halo 2 for Windows Vista won't install..

So I just found out that Halo 2 was released for Windows Vista. Grabbed a brand new copy (as in, “the Microsoft Certificate of Authenticity sticker on the case was unbroken” new), installed it, and tried to run it. I got the following error:

Live Gaming on Windows failed to initialize. This may be because another
LIVE Gaming on Windows application (such as the Halo 2 dedicated server) is
running on the same machine. Otherwise, reinstalling the game may fix this
problem.

No, I have not installed the Halo 2 dedicated server on my computer. No, reinstalling the game didn’t fix anything. Yes, I meet all the minimum requirements. No, the most recent version of Windows Live won’t install on my system either ( don’t know why, the installer tells me it encountered an error, but doesn’t have the decency to tell me what the error is…).

The computer I’m trying to install this on is an HP Pavilion dv6700-series laptop, with a copy of Windows Vista Home Premium 32-bit installed.

I would appreciate it if anyone could help with this. All that I’ve found over my past two days (yes, two days) of googling is how to fix this on Windows 7.

Try this:
http://www.xbox.com/en-AU/Live/PC/DownloadClient

Also, Halo 2 works on Windows Vista and newer, in case you didn’t know (just suprised you’re still using vista, is all)

So I tried to install the Live version at the link you provided, and it said I needed to also download and install Windows Live ID Sign In Assistant 6.5. This I did, and the installation failed due to an unknown error. And the game still doesn’t work. Any more ideas?

For what it’s worth, Halo 2 only seems to be taking up 3.7 GB of my hard drive, and minimum requirements for the game state that it needs 7 GB.

P.S. Still using Vista because I didn’t have the money to upgrade until now. Working on building a Windows 7 system.