Vista - failure to delete a registry key allocated to (possibly) non existent user sid

I am unable to delete a registry entry. The registry entry is inside a driver entry. When I try to read the entry I get access denied error. Logging as administrator using regedit with system account are of no use. I am unable to take ownership of the entry through that entry or through its parent (using replace ownership of key and its child keys options) have failed.

I think the failure is happening because the SID assigned to the entry is non existent - proabably a trick to not allow me to remove the service entry in registry. I would be grateful if somebody could suggest me a solution (The only solution I have not yet tried and am reluctant to is fixit tool from microsoft (it is going to be my last resort))

The problem started when I noticed that a driver file is being loaded at boot up time sptd.sys. I do not have any utility that should be using the driver (dameon tool, alcohol) - I do not want this driver - it may be a malware .

Any help would be great.

Thanks in advance.

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Most likely this can't be done because the program (and driver) are being used at that time.

Boot into Safe Mode and ensure that the driver isn't being loaded, then try it.

I'd recommend against messing with the registry in this way when there's many simpler ways to do this (services.msc, tweaking programs, etc).