apparently moving in certain ways performs special actions, because sometimes i'll be trying to highlight text on a page or just moving the mouse and the browser performs a Back action. or sometimes it'll suddenly highlight everything on the page. any way to turn these gestures off or at the very least find out how to perform them?

oh yeah, and i've got a toshiba satellite r15.

This is for a generic touchpad in a generic notbeook, I don't know about the R15 in particular, but should be similar.

In your system tray, there ought to be an icon for the touchpad. Click on the icon (may need to right click or double-click) and got to the tab for touchpad gestures/shortcuts. You should be able to configure as you wish.