Upgraded vista and want to restore

I purchased a Toshiba laptop in the end of 2007. two nights ago I found
a vista upgrade disk in the box and decided to install whatever was on
it thinking it would make my computer safer, more efficient, more
features, etc. After installation it deleted many of the features that
I was accustomed to having and also my anti virus. I am a novice with
computers and would like to know if it's possible to restore my computer
back to how it was before the upgrade. I've tried and the farthest back
it goes is the point when I first installed it. Any help would be
greatly appreciated. Paul.


--
COMMON