Forum - DLL-files.com

If your Windows is unable to run halo 2 due to a .dll error, it may be due to registry error. Such errors can heavily influence the performance of your computer. You should run free registry scan.

Download a rundll error repair tool and install it.
Click the Repair All Button. It will scan you computer.
Then, click the Repair All Button again.
Hopefully, it will help you.