Keyboard and touchpad problem with xp sp2

Archived from groups: microsoft.public.windowsxp.hardware (More info?)

Since installing xp sp2 on my Sharp laptop, the keyboard has become erratic -
unless I type very slowly, depressed keys do not always register.

In additon, the touchpad sometimes selects when it should be hovering.

I have checked the accessibility options and they are all disabled although
the computer appears to be responding as if they are on.

In my web searches, I have only found one unresolved problem of this type on
another message board

Help!!