I have searched these forums and the web but can't find anything on this.

I'm running Windows XP SP 3 on a Dell Inspiron 1501. I've recently uninstalled Avast, ran a registry cleaner afterwards to make sure it's completely gone, have disabled Windows Firewall, no other AV or Firewall running, every time I try to install Zonealarm free it gets to 10% installed and this error pops up:

"Installation encountered an error and cannot continue. You can try the installation again at a later time. Error# 1603: Fatal error during installation."

I've had Zonealarm installed on this machine successfully previously but had removed it completely, I also have it installed on various other machines and have never encountered this error before, and I can't find anything specific about what the error relates to.

Any ideas anyone?