M Service Failed to Start

Hi,

I'm getting the following error which seems to be causing my PC to freeze and it can only be unfrozen by powering off/on:

'The M service failed to start due to the following error: 
The system cannot find the file specified.'

Using the registry editor I found the following:

Computer\HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\M

I noticed that the ImagePath data is set to C 

Can anyone shed any light on what the M service is and how to rectify this?

Regards,

Rich