Dear Mr. Technical!
I really appreciate your offer of help...
Can you offer any suggestions for me?
Thank you, CoJo 
I had a similar problem. avast Home Edition and pieces of the Norton SystemWorks 2003 (except NAV) were incompatible! The solution was manually editing two Registry keys (apparently corrupted by Norton Anti-Virus Removal Utility).
Here we are! First of all, take it easy, relax, it's a long journey...

Do you have a XP system, ok?
Try to run avast! and clean your system before you go ahead...
1. Desinstall all Symantec Products (LiveRegistration and LiveUpdate included).
2. Boot.
3. Delete any folder related to their products: C:\Program files\Symantec, C:\Program files\Common files\Symantec Shared, C:\Program files\Norton SystemWorks
4. You will need a Registry Cleaner to remove the 'trash' left by Symantec.
There is a good one
here. It´s no more a freeware but you can use it to clean your system untill it expires.
5. Run
Norton Anti-Virus Removal Utility.
6. Boot
7. Install avast! again
8. You are almost there! Clean your system (through scan).
Tomorrow I'll teach you how to delete some 'invisible' trash left behind by Norton...
