Internet Explore 6.00 reinstall

System s/w is Win XP SP1

How do I install IE6 over an existing version. This is required as when I run IE6 it immediately displays “A problem has been encountered ….inform MS etc…””
The network is ok as I can ping the ISP’s server successfully. I can run Google Earth and access the web via this method OK. I tried to reinstall a new version of IE6 but that did not seem to work i.e. on the ADD/Remove Windows modules within the Add/Remove Progs, IE6 had 0Mb size.
I ran the setup but am not convinced it installed correctly.