Halo 2 on Vista problems

My installation of Halo 2 on Vista is not working. I get to the part where the Arbiter gets pushed off the ledge when Keyes gets captured and he loses the icon.

The game complains about needing the DVD, I insert it and I have to repeat the whole level. Twice. I’m taking a break but that is really a pain in the ass. I may re-install it and see if that fixes the problem.

So far the game is “okay”.