Possible inspiration(?):

We have the "problem" with our Win2K machine that automatic AV downloads don't always "take." That machine is the "master" for our internet connection sharing, so it's set up with an Administrator Account with strong password. Norton update can't install some updates unless the user logged on at the time of the download has Administrator privileges.

Win XP can be set up the same way, and if you have more than a single user logon it will create an Administrator account and automatically defaults all other users to "lesser privileges." "Power users" - the strongest non-Administrator status - may not be able to install some updates. With a new AV installation, there will almost always be some "program tweaks" with the first - or first few connections, so it's likely that you'll get some install failures or some "only part of it installs" with a new setup, if the Administrator - or the user who installed the program - is not the one logged on.

Once we got things sorted out on the Win2K, virus definitions seem to autoinstall, but anything that changes the AV program requires an Administer login and re-download of the update.

A complication is that if you installed a program while logged on as a specific user, generally that user has authority to change programs he/she instlled, but an update when another user with the same authority is on the machine an update may fail if it includes changes to the program.

We installed the AV under the Administrator account on the Win2K machine specifically so that crudware that attacks the AV itself has to get through the Windows privileges barrier to get to the AV program if a lesser user is on the machine.

Either Win2K or WinXP(pro) does allow for you to script privileges to a program, so that the program can "run as Administrator" regardless of who's logged on; but that gets into more advanced setup, and I haven't bothered.

If you use Norton "Live Update" Norton loads a small file to your machine that can look at what you have and figure out what updates you need. This speeds up the updates, since you only have to down load the specific stuff you need. A "Live Update Installer" also should download, and may be updated occasionally, although you may not notice that it's there. The installer should run automatically as soon as the new data and program files are downloaded. If the current user at the time of the update lacks the authority to make program changes, the installer may fail or may only install part of the update files.

I can't say this is the problem you had, but if you do have an Administrator account, you could try running the Live Update (clicky in Norton) while logged on as Administrator.

A workaround that sometimes works is to let the user most likely to be on the machine install the AV program under that user account logon. This usually will let anything affecting the program be successfully installed as long as that user is logged on. Just be sure to set the "share this program" so that running the AV won't cause permissions problems when someone else is signed on.

Note that all this really isn't a Norton thing - it's a Windows thing, and can pop up in any recent version of Windows, with or without the SP updates. If you've been getting critical updates, you probably have nearly all of what went into the SP packages. The exceptions would be the firewall update and some changes to settings.

WinXP SP1 does reset some permissions requirements, defaults the firewall to on, and adds several other "nice little features" that they neglect to tell you about. One thing I didn't expect is that it blocks sharing the root directory of the system drive with other machines on a local net, which meant we had to move a small number of shared data files into subfolders that could be shared. But it does work for most people, and they've had time now to get to know how to make it less troublesome.

John