Here's how I re-enabled my Synaptics Pointing Device touchpad functions -
Use a mouse to carry out the task below: Click Start > All Programs > Vaio Control Center > Keyboard and Mouse > Pointing Device > Enable > Apply > OK
Synaptics scrolling and pointing troubles appear to be common across many brands of laptop. I wrestled with it for hours; deleting, downloading and reinstalling drivers
three times, googling forums and boards, reading, troubleshooting, 2 System restores,,, oy!!!
Thank gawd I finally stumbled across this fix deep on another forum.
Hope this helps any new lost souls along the way.