Didn't notice this post until now:
Unfortunately, definitions of "really really old graphics card" differ between devs as well as between gamers...
In the grand scheme of things this game is not graphically intensive at all, but if you try playing the game on a laptop or any other computer that doesn't have a dedicated video card (ie you're using one of those integrated graphics chips from intel) you will probably not going to have a good time.
But as fate would have it I happen to have a computer in my house with this exact same problem (invisible models), so I suppose I can look into it. I've ignored the issue so far because it's an old piece of junk but I guess if I can get the game in a working state on that computer it should fix the issue for anyone else in the same situation too.
