Clie hotsink has failed on my Clie (PEG T615C. It's worked fine for
several months.  It failed to sinc after I downloaded a Windows
Security Patch.  After the usual soft and hard reset, restarts, etc I
tried reloading the Operating system from Clie installation CD. (under
Win XPPro).  Ive since restored WinXP to prior to that download (Have
I removed it or is it still lurking in my system?).  Re-installing
from CD yields a failure with a Palm Desktop error message: "An
installation support file
"C::\\Windows\Temp\{ba0f44c2-..........}_Isuser.dll" could not be
installed".  In going through many permutations, I have cleaned out my
input into the clie.  I had difficulty finding anything of value on
the Sony website.   Any help available?

You could try an update to the palm desktop software and hotsync found here
http://www.palm.com/us/support/downloads/ or here
http://www.ita.sel.sony.com/support/clie/t615/softupdates/