When I bought Radeon 9550 at Staples for $70.00, I was really happy. I thought...FINALLY, good graphics for Halo. I came home and installed the graphic card. I turned on the computer and started Halo. After waiting for like 20 seconds, there was an error box saying DirectDrive Acceleration problem. I was really pissed off. I searched the internet for like 10 min and found how to fix this problem.
First, you go to your halo folder.
Second, find a file called haloupdate.exe
Third, just run the file and wait until it updates.
Fourthly, the game should work now! Just run halo.exe and it should work now!