just trying to help, but it sounds like i bothered you.  i purchased a bunch
of vostros 1500 that came pre-loaded with xp and despite that they were
ordered without antivirus they came pre-loaded with norton that was
immediately removed.  these machines demonstrated the keyboard lad problem.
though symantec was uninstalled it didn't remove all the changes that the
installation had made to a system, and that includes the thousands of
entries appeared in the zones files.  as an example of the poor design of
norton they made these entries to the restricted site list in an attempt to
block malicious activity, but this approach to web content filtering has
other repercussions as ie7 and office are continuously checking what you
type to see if it is a web address and because of the long list of
restricted sites it results in the keyboard lag.  this is the fix that
worked for me.  perhaps the fix you provided the link to helps in other
situations for computers with the same symptom.  there is no law that says
the pcmservice problem is the only thing that can result in keyboard lag.