Windows 8 won't let me shut down the mouse pad on my HP G Series laptop like windows 7 did. It's a pain, I use an optic mouse...I keep hitting the pad by accident.

We would like to inform you that Windows has never had any feature which allowed turning the mouse pad off. This feature is sometimes provided by the mouse pad manufacturers.

Most laptops have an external switch or button, which when turned on, disable the mouse pad. You can try if this works.

You can also enable/disable the mouse pad from Control Panel.

Follow the steps below to do so:
a. Press Windows key + X and select Control Panel.
b. Select Mouse Properties.
c. Right-click on the mouse pad to enable/disable it.

The Mouse pad can also be disabled through the Device Manager.
a. Press Windows key + X and select Device Manager.
b. Expand Mice and other Pointing devices.
c. Right-click and Disable on the entry that says mouse pad or likewise.