I'm not exactly sure how this happened, but I think something uninstalled my computer's touchpad driver, as enhancements like momentum and gestures stopped working. I downloaded and installed an update, which did set up, but Synaptics' menu in Mouse options is missing, the gestures aren't back, and I got some error notification about the touchpad being non-authentic. I have not modified anything about this computer though, and have only recently messed with the drivers at all.
This is a HP Pavilion laptop, with a touchscreen, running Win8.1 64bit. The driver I installed came from the the Synaptics site's drivers page. Ask me if more details are needed.