This is my sense of what is happening in these cases: The machines are
infected with malware which has changed the permissions on a registry key in
such a way that the user, even if Administrator, doesn't have access to the
key.
In this circumstance, Microsoft Antispyware seems to get stuck, and leak
memory.
The fix is either to repair the permissions issue by hand, or find a
third-party tool which is able to deal with the malware. I can't give quick
easy advice about either choice, I'm afraid--if you are knowledgable about
taking ownership and setting permissions, that's what needs to be done.
Knowing the name of the key where it is sticking might help ID the culpret.
