If someone else is having the same problem after trying all the options, you can try this .reg file:
For me it works and now i can press only once the keyboard key and delete all words.
Save to a .reg file:
Windows Registry Editor Version 5.00
[HKEY_CURRENT_USER\Control Panel\Accessibility\Keyboard Response]
"Last Valid Wait"=dword:00000000
"Last Valid Delay"=dword:000003e8
"Last Valid Repeat"=dword:000001f4
"Last BounceKey Setting"=dword:00000000
"Flags"="59"
"DelayBeforeAcceptance"="0"
"AutoRepeatRate"="20"
"AutoRepeatDelay"="440"
"BounceTime"="0"
Source: http://www.msfn.org/board/topic/173128-fix-for-hyper-fast-win-10-keyboard-repeat/
