Here is a good gravemind fix too, it fixes it permanently if you always load the game with the loaderplus

Directions inside

If you are on XP and used the crack and can't get past Gravemind here is a working patch.

nfo:
Halo 2 XP Gravemind level fix

This is alpha quality so use at own risk. I've tested it on two systems and it
seems to work fine.

to use:

1) copy WowMon.dll and Loaderplus.exe into your Halo 2 directory (same place
as wow.dll and loader.exe)
2) start Halo2 using "loaderplus halo2.exe" from the command line at the
Halo 2 installation directory. Alternatively, change your Halo 2 startup
shortcut (if you have one) to use loaderplus.exe instead of loader.exe
3) play Halo 2

Technical explanation of Gravemind level problem (if you care):

It seems that on some systems (presumably those with lots of RAM) Halo2
tries to load a single 75mb clip of the level. This operation fails on XP as
it does not support asynchronous reads larger than 64mb (you can verify this
by running filemon from sysinternals). For whatever reasons Halo2 treats
this failure to read as a corrupted (or partially installed) map and asks
for the original CD. I'm guessing that this only happens on Gravemind
because it is the biggest level in the game.

The WowMon.dll file in this archive intercepts large ReadFile calls and
splits them up into several chunks smaller than 64mb. Loaderplus.exe is a
modified version of abcba's loader.exe that just loads WowMon.dll in
addition to Wow.dll

Share and Enjoy,

grue697


PS. Big thanks to abcba for getting Halo 2 to work under XP, awesome work
dude.