When un installing use the ready made uninstaller that is in the main FeralHeart folder. Once you have un installed it from there, delete the FeralHeart folder afterwards, then re-install the game from the 'Download' button, not the torrent. If it still isn't opening then try right clicking the game icon on your desktop and select 'open as administrator'.
Still not working? Then go into your new FeralHeart folder and open up the 'ogre' config file in notepad and replace what is inside with this:
Render System=OpenGL Rendering Subsystem
[OpenGL Rendering Subsystem]
Colour Depth=32
Display Frequency=N/A
FSAA=0
Full Screen=No
RTT Preferred Mode=FBO
VSync=No
VSync Interval=1
Video Mode=1280 x 800
sRGB Gamma Conversion=No
[Direct3D9 Rendering Subsystem]
Allow NVPerfHUD=No
FSAA=None
Floating-point mode=Fastest
Full Screen=No
VSync=No
Video Mode=800 x 600 @ 32-bit colour
sRGB Gamma Conversion=No
Make sure to click save after! Once that is done, re-launch FeralHeart or restart your computer for the programming to kick in. Good luck!