When you created a new user a new /home should have been created if you chose that option. That would mean the new user would have had a clean .kde4 folder as well as all the others. Did you choose to make a new /home for your new user?
As PClinuxOS is based on Mandriva, which I run, it is quite easy to set up a new user with a new /home. If it doesn't work it is then a simple matter to delete the new user along with any files created for that user. If you do create a new user with a dedicated /home and you get the same symptoms then it is something that is not in your /home so deleting any files in your /home should not make any difference.
I hope that makes sense Mike.