You running build 7000 or an earlier one? Ack I think I got it, whichever genius made the Halo 2 XP hack (which I use) made it put the files in the Halo 2 game directory, including a stub dwmapi.dll. That's probably causing the error. Dunno why I didn't notice it before. OK New problem! Games For Windows Live goes into an infinite update loop even though I am positive I already have the latest Halo 2 patch. It's downloaded and applied the patch 3 times already and I've applied it manually as well but it still claims it can't let me sign onto Live without patching it. Interestingly I had the same behavior while using the XP hack (I am positive it is completely removed) and I assumed it was a bug with said hack. Apparently not. Aha figured it out, apparently some DLL files had screwed up NTFS permissions and the update couldn't write to them so it just gave up (but still claimed it was successful). Wiped them using FileASSASSIN and reinstalled and I THINK the update worked properly this time. [Edited on 01.23.2009 10:55 AM PST]