super disappointed Norton behavior!

I have not been able to evaluate this software
Why?
During installation, the system tells me 7 "traces" of an old installation of other software like Norton
I learn about the Web
Problem widely known!
Clean Norton, actually
So I use "Revo Uninstaller Pro" to perform a complete uninstall +
In fact, although identifies the presence of traces of previous Norton Utilities 14/15
I believe saved me since it seems to thorough cleaning in the registry.
However, after each time, uninstall my antivirus Avast Internet Security no avail:
inability to install this software!
I am very disappointed
However, to have investigated extensively on the Web, I am not alone in this case.
Norton products seem particularly likely
Moreover, friends have informed me exactly the same disappointments
I do know actually think of this software and its type of protection
Wicked disappointment