Nevermind. I finally figured it out after messing around for a couple hours. In Control Panel -> Hardware and Sound under Devices and Printers there is a link for Mouse. From the Mouse properties window which pops up after you click that link, select the 'Device Settings' tab. Hopefully the Synaptics Touchpad device will be shown. Select it and then click the Disable button.
NOTE: it does not appear that the touchpad can be disabled through the Device Manager interface nor BIOS.