Windows Explored

The other day while trying to remove some add-ons from Internet Explorer, Windows DEP was kicking in and closing the IE Setting control panel box (rundll32.exe process) for whatever reason:

Or at least it was trying to.

The process was, in fact, getting hung and I couldn’t kill it from the Task Manager. Looking with Process Explorer, I could see that rundll32.exe was crashing. As a result, the Windows XP default post-mortem debugger, Dr. Watson, was launching as a child process of rundll32.exe and trying to dump it, but was itself getting hung:

To workaround this type of un-killable processes, check for any child processes the parent process has spawned and kill them first. In the case here, killing drwtsn32.exe was enough to allow rundll32.exe to exit without the need for rebooting.

In rare but extreme cases, it’s not unheard of to encounter processes that can’t be killed at all except by rebooting. You can experiment with un-killable processes by using NotMyFault. There is also a good Mark Russinovich blog on un-killable processes here:
http://blogs.technet.com/b/markrussinovich/archive/2005/08/17/unkillable-processes.aspx