A. I recently had this exact problem with some Antivirus processes I could not kill, it said I had insufficient access so all I did was start a Task Manager session under the 'System' process by submitting with the AT command, for example
C:\> <b>at <time one minute in the future> /inter taskmgr.exe</b>
When Task Manager starts you should be able to stop anything (but be CAREFUL!).
An alternative to AT would be the SOON resource kit command and the syntax would be
C:\> <b> soon 30 /interactive taskmgr</b>
Another option would be to use the the PVIEW resource kit utility to change the security on the process and then stop as normal.
Another way would be to use the kill -f command but you would need to be a local Administrator of the machine. You could use the Resource kit PULIST.EXE program to view the processes.