Why won't 18 Wheels of Steel Haulin' run on my computer?

18 Wheels of Steel Haulin’ used to run on my computer a few years ago. Then we got the computer upgraded and now this game runs really choppy. I noticed in the system requirements it says something about a T&L compatible video accelerator card. I’m thinking that this may have something to do with the game running choppy. What driver do I need to download in order for this game to work right? I am dying to play this game but I haven’t been able to for a couple of years. This is one of my all-time favorite games.