Well, as a Christmas Eve present, here is something I remembered later which may also help, Ronald, and also Cathy et al.
By the way, there are other threads like this one, and often enough the bad/missing permissions for Registry entries turns out to be the problem. I just happened to run across one looking for something else.
What I remembered is this. The original installation of CS3 didn't work the first time. I was able to get it to succeed, by forcing non-microsoft services and startup applications not to run while I did the installation.
Naturally I disconnected the internet (including wireless) completely before trying any of this, as all my firewall and virus protection would be removed by rebooting without those services. Otherwise you are almost sure to get one of the prevelant worms/viruses or worse - generally in a few seconds (yes, it's that bad out there).
I had posted pseudo-instructions here, but took them out, as I think they are too dangerous even at that level, unless you know exactly what you are doing. If not, find someone who does. I think there may be procedures actually in some of the Adobe material, but again, not for anyone who doesn't understand precisely.
Anyway, my theory now is that virus protection is what prevented the first install completing correctly, and left badly permissioned registry entries. Those bad permissions led to later updater failures, as above. It wasn't enough to turn off my virus protection normally - the install still failed, so probably this is a base level of protection.
Why Microsoft doesn't allow their installer to work under Safe Boot, which ties Adobe's hands and would otherwise clean up these issues, is a mystery.
Hope it's some help, whether you also need an expert person to assist appropriately, or not.
And best holiday greetings.
