Igor,
perhaps I should clarify.
In my attempt to install Beta 4.5 I have created a problem when comp had been ok.
In attempts to repair this caused comp to freeze so I used system restore, which got comp working.
I am now using 4.1.512 but 4.5 is lurking in the background because if I went into avast menu and attempted to update programme then it would if I let it install 4.5 again along with problems.
What I wish to do is remove all traces of avast av and then reinstall 4.1.512
to get me back to when all was ok. I could do that from CD.
Then if then all ok with 4.1.512 await the release version of 4.5.
I have to go out for a while so will follow up when I return.
Thanks a lot Mal