text: what free programs are out there to download for molecular modeling? i have tried chimera but i think it has a compatibility issue with video card (sis vga 760). looking for a similar "cutting edge" program. i use isis draw 2.5.  it's completely free and fairly easy to use.  if you need space-filling modelling, i'm not sure that it will do that.  it does check your model and will alert you of mistakes though.  it has some nice capabilities.  if you would like, i can send it to you.  email me at javert99 at yahoo dot com if you are interested.