Hi, Just purchased ESS and downloaded the .msi When I try to run I get the "This installation package could not be opened" message. I followed this kb article, and subsequently this MS kb article. When prompted to reinstall Windows Installer I received this message... I am running XP-SP3 on a Samsung netbook which is about 6 hours old. It came with a Norton trial which I completely uninstalled before purchasing a new license from yourself. Hope you can help before I tear the rest of my hair out...
Did you remove any Norton leftovers with Norton Removal Tool (SymNRT) 2009.0.5.26? If not, try running that and see if it solves the problem.