I found this on XDA - it was originally posted by Psyki. I ran into this after flashing to a new ROM, and every time I pressed one of the hard keys the phone would vibrate.
Try setting this registry key to disable vibration when you use the hardware keys:
Code:
[HKEY_LOCAL_MACHINE\Software\OEM\KeyState]
"KeyVibratorState"=dword:00000000
This worked for me - no soft reset required. I hope it comes in handy for someone!