How can I use the Toshiba Function Keys on my Satellite C655D-S5226 without being required to install the huge (40 Mb!) Toshiba Function Key Driver?
Coincidentally, I recently disabled the Toshiba Function Key Main Module (TCrdMain) and Toshiba Hotkey Driver (Thotkey) using the MS Sysinternals app, Autoruns v. 13.01 and notice no difference in behavior in Window 8.1. The function keys behave normally without pressing Fn (as desired), and with Fn, perform the expected secondary funtions, e.g. F2 dims the screen, F11 mutes sound.
Using Autoruns, https://technet.microsoft.com/en-us/sysinternals/bb963902, or Nirsoft's WhatsInStartup, http://nirsoft.net/utils/what_run_in_startup.html, allows you to disable (or to re-enable) these utilities with a click in a checkbox, so there's little risk or effort in testing.