I'm noticing now too that it's not just disabling itself. After installing the Toshiba Value Added Package and the Synaptics driver, the only change is that now I can see a big icon in the center of the screen alert me when the state of the mouse switches from enabled to disabled. Even during the Windows installation, the mouse continually disabled itself. When this happened, I took it as a sign that it was time to reformat the hard drive and start fresh. I know I'm not pressing either of these by accident when the mouse turns off. The only way to get it back is by pressing FN+F9 or sometimes to press the enable/disable button immediately above the mouse. I'll be typing along, or moving the mouse, or just doing nothing at all (waiting for a download to finish, for instance) and the mouse will become suddenly disabled.
The device is listed as a Synaptics Touchpad V7.2. My Toshiba touchpad has developed a bad habit of disabling itself at random.