If you want to enable voice command from a bluetooth headset, check that the registry is ok. 

Use a registry editor like "PHM Registry Editor" .

Go to HKEY_LOCAL_MACHINE\SOFTWARE\OEM\VoiceCommand and check the following parameters :

• LaunchAPEnable=1
• VoiceCmdEnable=1
• Path=\Program Files\Voice Command\voicecmd.exe (or another path if you have installed it to a memory card)

With Microsoft Voice Command 1.5, it should works.