Problems installing Norton AntiVirus 2009

I received a notice from Norton inviting me to upgrate to AntiVirus 2009.  I downloaded the software and followed the installation instructions.  It seemed to install properly, requiring to reboot a couple of times through the procedures.  Once it was done, when it rebooted, it gave me a window asking me to uninstall AntiVirus, there were only two options offered: custom unistall and complete uninstall, no options to ignore or cancel.  So I clicked on custom uninstall, and it started an uninstall process.  Half way through, I got an error message from Windows saying “Windows must now restart DCOM Server Process launcher service terminated unexpectedly”.  Window then shut itself down, but when I rebooted, there was no sign of Norton anywhere on my computer.  I don’t know what to do.