The mouse on the nc6000 hasn't jumped for 3 days running, so I am marking this thread solved. The basic problem was that I was putting the synaptics code in the wrong file. It needed to go into xorg.conf. Once having done that, it got better, but was still quirky. I then changed the refresh rate and the horizontal sync in xorg.conf. Basically, I took the horizontal sync from xorg.conf in my omnibook, and set the refresh rate to 60. That seems to work.
Thanks to all.