I was a little confused about patches and such, but when I borrowed the game off my friend, I installed Icewind Dale and Heart of Winter. to try and cure the skipping, I installed the patch for 1.06, and it really messed up my game, and my potion bag and scroll case went missing, along with a couple of my character portraits. I asked my friend and he told me that I don't need a patch if I have Heart of Winter, so I uninstalled it all and reinstalled Icewind Dale and Heart of Winter, and now, while the game still runs, it also still skips.
I find that it tends to not skip when I first start the game, and I found that if it starts to skip badly, restarting my comp helps. I reckon therefore that it might be a memory issue? Mine doesn't freeze completely, so I think I might actually have a different problem from BlakJak, or his might just be that much worse.
Anyway, I have the feeling that I'm talking crap so if anybody understood everything I just said, then well done