A ch iinteressasse, ho trovato la soluzione utilizzando le Windows API:

import win32pdhutil
import win32api
import win32con

proc_name = 'explorer'
pid = win32pdhutil.FindPerformanceAttributesByName(proc_ name) #ricava il pid del processo explorer.exe
print pid

handle = win32api.OpenProcess(win32con.PROCESS_TERMINATE, 0,pid[0])
win32api.TerminateProcess(handle,0) #lo termina