Sorry for how incredibly ugly this is, I just wanted to get some basic images on there for anyone to follow. I couldn't find ANY info on this when I first got Vista, and only managed to figure it out by luck and messing with EVERYTHING. xD
If you have Vista (or Windows 7) and are having problems with your tablet (outside of an art program, in vista. Apparently it messes up even in art programs for 7, or so I've been told.) Lagging badly, and refusing to draw if you only make a short line, or making jagged lines then this may be your problem.
Hopefully disabling these options will fix things for you, but I can't guarantee that they will. I just hope they do, because those problems are MISERABLE.