Vostro 1500 Touchpad Jumping, Irregular Behavior

I saw a previous post about this, but it fizzled out late 2007...  Is there any update on how to fix the Synaptics Touchpad "jumping" around?  It is 100 times better when I run on battery and marginal whenevr the laptop is plugged in.

I read that some people have replaced their power cords and that had fixed the problem, but one would think if the power cord was truly faulty in early 2007, they would stop manufacturing them by Feb 08.  I just purchased this laptop a week ago and the touchpad is getting very irritating.

Any updates?  And, is this truly due to electrical interference from a power cord?  I find that hard to believe.  I would expect that if anything it is due to some internal voltage irregularities or something due to something regulating voltage on the laptop, not the cord...  But I am nto electrical engineer either...

Thanks!

Dan