Enabled Show Hidden Devices.
Deleted (Uninstalled) all non-connected HID devices (the ones with lighter color).
Unplugged my keyboard/mouse dongle - BESIDES my keyboard, I have another wireless always connected, so I can play movies while on my bed.
Deleted those now-greyed-out devices (from the unplugged dongle).
Voilá: Game started up just fine.
So... Definitely HID devices.
Thanks for the info :)
PS: *LAME* that you have to do this :(