I've run in thread degraded mode for 2 or 3 weeks without a hitch before, this time I wasn't so lucky.  After about 6 hours explorer spun up taking 50% CPU (given it's a HT machine, that usually means 1 thread spinning endlessly).  Heuve!  That just won't do.  But we can merely degrade this thread too ... once we find it ...

So I ctrl-C in the debugger window that got started from part 1 ...
Alternatively: If you don't have debugger attached up to the process yet, you can do so, by going to the C:\debuggers directory (expained in part 1), typing "tlist" to find the Process ID (PID) of the explorer.exe process, and then run "ntsd -p <PID>".
At the debug prompt we type "!runaway", which gives you something like this:
    0:076> !runaway
     User Mode Time
      Thread       Time
      73:1acc      0 days 6:36:51.328
       1:ec0       0 days 1:39:27.203
      15:1ac       0 days 0:06:01.640
      12:f94       0 days 0:05:44.281
    ... deleted the other ~80 threads ...
The time column is cumulative CPU time the thread has used.

At this point you 'g' the debugger, wait for a short timed interval, then hit ctrl-C again to re-break into the debugger.  I waited 30 seconds myself, and then re-run the !runaway command ...
    0:082> !runaway
     User Mode Time
      Thread       Time
      73:1acc      0 days 6:37:21.359
       1:ec0       0 days 1:39:28.406
      15:1ac       0 days 0:06:01.671
      12:f94       0 days 0:05:44.281
You can see from the blue that thread 73 is our culprit, as it's cumulative CPU time went up by nearly exactly 30 seconds.  Note the culprit thread isn't guaranteed to be the top thread, but it was in my case.

So the "~f" command from the first blog affects the "current" thread in the debugger, which you can see above is thread 82, not exactly, well ... not at all what is desired.  We want thread 73 to be frozen though, so here is how you freeze a specific thread:
    0:082> ~73f
    0:082> g
Now I'm back to normal, CPU settles down, go back to work.

Sometime later the next thing is I AV'd when I typed a search in the MSN Desktop Search box on the task bar see the bottom of my start bar ... since MSN DS was the source of the original issue,
not sure why I'd have expected that to work (I can be really stupid sometimes, I'll blog more about that), one more thread to freeze and then 'g' the process.

The last thing that AV'd is <window>-E.  Don't know why that AV'd, but don't care I can live without file explorer.

Though I am not sure I can live without desktop search ... I sense a reboot is in my future ...