You've disabled it computer wise. How so?
I'd suggest uninstalling and reinstalling Feral Heart.
If you have Windows 7/8, you could try this method:
Click on Start.
Click on Control Panel.
In the search bar of the Control Panel window (top right)
Type: Keyboard.
Under Character Repeat, move the repeat delay slider to the left or right to increase or decrease how long you must hold down a key before the keyboard character repeats, and then click OK.
You could also try updating your Drivers or doing a Windows Update to fix some problems.
As a last resort, I would download SharpKeys and disable 5 from your computer Registry. Here's a link to SharpKeys and a YouTube video on how to disable a key from the Registry:
https://sharpkeys.codeplex.com/https://www.youtube.com/watch?v=uId_uyirZU4