The only things I can think of to recommend is to try the patch and launcher.
For your convenience, click
here, and find the Grim Fandango Launcher, then click
here for the patch.
Install both.
A neat little thing about the Launcher is that it will let you copy the CD-ROMs onto your hard drive, so you don't need to have the CDs in the drive to play the game, which helps it run smoother and faster.