Windows Installer "MainSP2ff.msp" and other error messages

[DBQ David]

As I was manually removing a Symantec product via regedit, I accidentally
deleted the following key:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Installer\UserData\S-1-5-18

That wiped out the rest of the key: \products\

I should have backed up my registry file, but I didn't.

I also tried System Restore, but it couldn't find a usable restore point
prior to my mistakes.

Now Windows Installer looks for, but cannot find, the following files:

MSBCM.MSI
on bootup
when I send email from home via a web access email program at the office.
MainSP2ff.msp
on opening IE
on opening Outlook
when I send email from home via a web access email program at the office
when I open an attachment from home via a web access email program at the
office
when I open "resources" in a non-Windows, Windows-compatible program
Symantec Client Security.msi (I've uninstalled this program, as well as
Symantec Antivirus.)
when I open Windows Explorer and any new IE windows

For each of these I get multiple Windows Installer dialogue boxes. If I
click on "cancel," the boxes disappear and the programs run properly; but it
can take up to three or four repetitions of the same dialogue boxes before it
lets the program proceed.

My questions are:

[1] Can someone help me reconstruct the ...\product\ key?
[2] Or would you suggest some other solution?

When I open Outlook 2007 for the first time, I get an error message re:
Symantec Antivirus add-in.... Outlook 2007 says I need to uninstall the
Symantec Antivirus add-in from Outlook. I've already uninstalled it, and I
thought I had removed all traces of Symantec products on my computer.

 

[Mark L. Ferguson]

The only resonable try at fixing that is to import the key from a working
copy. If none exist, it's doubtful that anything you do is going to work.
This is a 'profile' key. If you have a profile that 'works', you might copy
its /products/ over. Hard to say whether that would work or not.

In any case, building a new user ID is your first step.
811151 - How to Copy User Data to a New User Profile:
http://support.microsoft.com/default.aspx?scid=kb;en-us;811151